Boy, October, and War (1980-84)

Island Records signed U2 in March 1980, and in May the band released "11 O'Clock Tick Tock" as their first international single. The band's debut album, Boy, followed in October. Produced by Steve Lillywhite, it received generally positive reviews. Although Bono's unfocused lyrics seemed improvised, they expressed a common theme: the dreams and frustrations of adolescence. The album included the band's first United States hit single, "I Will Follow". Boy's release was followed by the Boy Tour, U2's first tour of continental Europe and the United States. Despite being unpolished, these early live performances demonstrated U2's potential, as critics noted that Bono was a "charismatic" and "passionate" showman.

The band's second album, October, was released in 1981 and contained overtly spiritual themes. During the album's recording sessions, Bono and the Edge considered quitting the band due to perceived spiritual conflicts. Bono, the Edge, and Mullen had joined a Christian group in Dublin called the "Shalom Fellowship", which led them to question the relationship between the Christian faith and the rock and roll lifestyle. Bono and the Edge took time off between tours and decided to leave Shalom in favour of continuing with the band. Recording was further complicated when a briefcase containing working lyrics and musical ideas was lost during a performance at a nightclub in Portland, Oregon. The album received mixed reviews and limited radio play. Low sales outside the UK put pressure on their contract with Island and focused the band on improvement.

Resolving their doubts of the October period, U2 released War in February 1983. A record on which the band "turned pacifism itself into a crusade", War's sincerity and "rugged" guitar was intentionally at odds with the trendier synthpop of the time. The album included the politically charged "Sunday Bloody Sunday", in which Bono lyrically tried to contrast the events of Bloody Sunday with Easter Sunday. Rolling Stone magazine wrote that the song showed the band was capable of deep and meaningful songwriting. War was U2's first album to feature the photography of Anton Corbijn, who remains U2's principal photographer and has had a major influence on their vision and public image. U2's first commercial success, War debuted at number one in the UK, and its first single, "New Year's Day", was the band's first hit outside Ireland or the UK.

On the subsequent War Tour, the band performed sold-out concerts in mainland Europe and the US. The sight of Bono waving a white flag during performances of "Sunday Bloody Sunday" became the tour's iconic image. U2 recorded the Under a Blood Red Sky live album and the Live at Red Rocks concert film on tour, both of which received extensive play on the radio and MTV, expanding the band's audience and showcasing their prowess as a live act. With their record deal with Island Records coming to an end, the band signed a more lucrative extension in 1984. They negotiated the return of their copyrights (so that they owned the rights to their own songs), an increase in their royalty rate, and a general improvement in terms, at the expense of a larger initial payment.

The Unforgettable Fire and Live Aid (1984-85)

"We knew the world was ready to receive the heirs to The Who. All we had to do was to keep doing what we were doing and we would become the biggest band since Led Zeppelin, without a doubt. But something just didn't feel right. We felt we had more dimension than just the next big anything, we had something unique to offer."

The band feared that following the overt rock of the War album and tour, they were in danger of becoming another "shrill", "sloganeering arena-rock band". Thus, they sought experimentation for their fourth studio album, The Unforgettable Fire; as Adam Clayton recalls, "We were looking for something that was a bit more serious, more arty." The Edge admired the ambient and "weird works" of Brian Eno, who, along with his engineer Daniel Lanois, eventually agreed to produce the record.

Partly recorded in Slane Castle, The Unforgettable Fire was released in 1984 and was at the time the band's most marked change in direction. It was ambient and abstract, and featured a rich, orchestrated sound. Under Lanois' direction, Mullen's drumming became looser, funkier, and more subtle, and Clayton's bass became more subliminal. Complementing the album's atmospheric sound, the lyrics are open to interpretation, providing what the band called a "very visual feel". Due to a tight recording schedule, however, Bono felt songs like "Bad" and "Pride (In the Name of Love)" were incomplete "sketches". The album reached number one in Britain, and was successful in the US. The lead single "Pride (In the Name of Love)", written about Martin Luther King, Jr., was the band's biggest hit to that point and was their first song to chart in the US top 40.

Much of The Unforgettable Fire Tour moved into indoor arenas as U2 began to win their long battle to build their audience. The complex textures of the new studio-recorded tracks, such as "The Unforgettable Fire" and "Bad", were problematic to translate to live performances. One solution was programmed sequencers, which the band had previously been reluctant to use, but are now used in the majority of the band's performances. Songs on the album had been criticised as being "unfinished", "fuzzy", and "unfocused", but were better received by critics when played on stage.

U2 participated in the Live Aid concert for Ethiopian famine relief at Wembley Stadium in July 1985. U2's performance in front of 72,000 fans in the stadium in an event that had a worldwide television audience of two billion people was a pivotal point in the band's career. During a 14-minute performance of the song "Bad", Bono leapt down off the stage to embrace and dance with a fan, showing a television audience the personal connection that Bono could make with audiences. In 1985, Rolling Stone magazine called U2 the "Band of the '80s", saying that "for a growing number of rock-and-roll fans, U2 have become the band that matters most, maybe even the only band that matters".

The Joshua Tree and Rattle and Hum (1986-90)

"The wild beauty, cultural richness, spiritual vacancy and ferocious violence of America are explored to compelling effect in virtually every aspect of The Joshua Tree—in the title and the cover art, the blues and country borrowings evident in the music ... Indeed, Bono says that 'dismantling the mythology of America' is an important part of The Joshua Tree's artistic objective."

For their fifth album, The Joshua Tree, the band wanted to build on The Unforgettable Fire's textures, but instead of out-of-focus experimentation, they sought a harder-hitting sound within the limitation of conventional song structures. Realising that "U2 had no tradition" and that their knowledge of music from before their childhood was limited, the group delved into American and Irish roots music. Friendships with Bob Dylan, Van Morrison, and Keith Richards motivated the band to explore blues, folk, and gospel music and focused Bono on his skills as a songwriter and lyricist. U2 interrupted the album sessions in mid-1986 to serve as a headline act on Amnesty International's A Conspiracy of Hope tour. Rather than being a distraction, the tour added extra intensity and focus to their new material. Later that year, Bono travelled to San Salvador and Nicaragua and saw first-hand the distress of peasants bullied in internal conflicts that were subject to US political intervention. The experience became a central influence on the new music.

The Joshua Tree was released in March 1987. The album juxtaposes antipathy towards US foreign policy against the group's deep fascination with the country, its open spaces, freedom, and ideals. The band wanted music with a sense of location and a "cinematic" quality, and the record's music and lyrics draw on imagery created by American writers whose works the band had been reading. The Joshua Tree became the fastest-selling album in British chart history, and topped the Billboard 200 in the United States for nine consecutive weeks. The first two singles, "With or Without You" and "I Still Haven't Found What I'm Looking For", quickly became the group's first number-one hits in the US. They became the fourth rock band to be featured on the cover of Time magazine, which declared that U2 was "Rock's Hottest Ticket". The album won U2 their first two Grammy Awards, and it brought the band a new level of success. Many publications, including Rolling Stone, have cited it as one of rock's greatest. The Joshua Tree Tour was the first tour on which the band played shows in stadiums, alongside smaller arena shows.

The documentary Rattle and Hum featured footage recorded from The Joshua Tree Tour, and the accompanying double album of the same name included nine studio tracks and six live U2 performances. Released in October 1988, the album and film were intended as a tribute to American music; they included recordings at Sun Studios in Memphis and performances with Bob Dylan and B. B. King. Rattle and Hum performed modestly at the box office and received mixed reviews from both film and music critics; one Rolling Stone editor spoke of the album's "excitement", another described it as "bombastic and misguided". The film's director, Phil Joanou, described it as "an overly pretentious look at U2". Most of the album's new material was played on 1989's Lovetown Tour, which only visited Australasia, Japan and Europe, so as to avoid the critical backlash the group faced in the US. In addition, they had grown dissatisfied with their live performances; Mullen recalled that "We were the biggest, but we weren't the best". With a sense of musical stagnation, Bono said to fans on one of the last dates of the tour that it was "the end of something for U2" and that they had to "go away and ... just dream it all up again".

Achtung Baby, Zoo TV, and Zooropa (1990-93)

"Buzzwords on this record were trashy, throwaway, dark, sexy, and industrial (all good) and earnest, polite, sweet, righteous, rockist and linear (all bad). It was good if a song took you on a journey or made you think your hifi was broken, bad if it reminded you of recording studios or U2 ..."

Stung by the criticism of Rattle and Hum, the band sought to transform themselves musically. Seeking inspiration on the eve of German reunification, they began work on their seventh studio album, Achtung Baby, at Hansa Studios in Berlin in October 1990 with producers Daniel Lanois and Brian Eno. The sessions were fraught with conflict, as the band argued over their musical direction and the quality of their material. While Clayton and Mullen preferred a sound similar to U2's previous work, Bono and the Edge were inspired by European industrial music and electronic dance music and advocated a change. Weeks of tension and slow progress nearly prompted the group to break up until they made a breakthrough with the improvised writing of the song "One". They returned to Dublin in 1991, where morale improved and the majority of the album was completed.

Achtung Baby was released in November 1991. The album represented a calculated change in musical and thematic direction for the group; the shift was one of their most dramatic since The Unforgettable Fire. Sonically, the record incorporated influences from alternative rock, dance, and industrial music of the time, and the band referred to its musical departure as "four men chopping down the Joshua Tree". Thematically, it was a more introspective and personal record; it was darker, yet at times more flippant than the band's previous work. Commercially and critically, it has been one of the band's most successful albums. It produced five hit singles, including "The Fly", "Mysterious Ways", and "One", and it was a crucial part of the band's early 1990s reinvention. Like The Joshua Tree, many publications have cited the record as one of rock's greatest.

Like Achtung Baby, the 1992-1993 Zoo TV Tour was an unequivocal break with the band's past. In contrast to the austere stage setups of previous U2 tours, Zoo TV was an elaborate multimedia event. It satirised the pervasive nature of television and its blurring of news, entertainment, and home shopping by attempting to instill "sensory overload" in its audience. The stage featured large video screens that showed visual effects, random video clips from pop culture, and flashing text phrases. Whereas U2 were known for their earnest performances in the 1980s, the group's Zoo TV performances were intentionally ironic and self-deprecating; on stage, Bono performed as several over-the-top characters, including "The Fly", "Mirror Ball Man", and "MacPhisto". Prank phone calls were made to President Bush, the United Nations, and others. Live satellite link-ups to war-torn Sarajevo caused controversy.

Quickly recorded during a break in the Zoo TV Tour in mid-1993, the Zooropa album expanded on many of the themes from Achtung Baby and the Zoo TV Tour. Initially intended as an EP, Zooropa ultimately evolved into a full-length LP album. It was an even greater departure from the style of their earlier recordings, incorporating further dance influences and other electronic effects. Johnny Cash sang the lead vocals on "The Wanderer". Most of the songs were played at least once during the 1993 legs of the tour, which visited Europe, Australia, New Zealand and Japan; half the album's tracks became permanent fixtures in the setlist. Although the commercially successful Zooropa won the Grammy Award for Best Alternative Music Album in 1994, the band regard it with mixed feelings, as they felt it was more of "an interlude".

On the final leg of the tour, Clayton was unable to perform for the group's 26 November 1993 show in Sydney, the dress-rehearsal for filming Zoo TV: Live from Sydney, due to a hangover. Bass guitar technician Stuart Morgan filled in for him, marking the first time any member of U2 had missed a show. After the incident, Clayton gave up drinking alcohol.

Passengers, Pop, and PopMart (1994-99)

In 1995, following a long break, U2 contributed "Hold Me, Thrill Me, Kiss Me, Kill Me" to the soundtrack album of the film Batman Forever. Later that year, the band released an experimental album called Original Soundtracks 1. Brian Eno, producer of four previous U2 albums, contributed as a full partner, including writing and performing. For this reason and due to the record's highly experimental nature, the band chose to release it under the moniker "Passengers" to distinguish it from U2's conventional albums. Mullen said of the album, "There's a thin line between interesting music and self-indulgence. We crossed it on the Passengers record." It was commercially unnoticed by U2 standards and it received generally mixed reviews. However, the single "Miss Sarajevo" featuring Luciano Pavarotti, was among Bono's favourite U2 songs.

"It's not enough to write a great lyric; it's not enough to have a good idea or a great hook, lots of things have to come together and then you have to have the ability to discipline and screen. We should give this album to a re-mixer, go back to what was originally intended ..."

On 1997's Pop, U2 continued experimenting with dance club culture; tape loops, programming, rhythm sequencing, and sampling provided much of the album with heavy, funky dance rhythms. Released in March, the album debuted at number one in 35 countries and drew mainly positive reviews. Rolling Stone, for example, stated that U2 had "defied the odds and made some of the greatest music of their lives"; others felt that the album was a major disappointment. Sales were poor compared to previous U2 releases. The band was hurried into completing the album in time for the impending pre-booked tour, and Bono admitted that the album "didn't communicate the way it was intended to".

The subsequent tour, PopMart, commenced in April 1997. Like Zoo TV, it poked fun at pop culture and was intended as a send-up of commercialism. The stage included a 100-foot (30 m) tall golden yellow arch (reminiscent of the McDonald's logo), a 150-foot (46 m) long video screen, and a 40-foot (12 m) tall mirrorball lemon. U2's "big shtick" failed, however, to satisfy many who were seemingly confused by the band's new kitsch image and elaborate sets. The postponement of Pop's release date to complete the album meant rehearsal time for the tour was severely reduced, and performances in early shows suffered. Despite the mixed reviews and difficulties of the tour, Bono considered PopMart to be "better than Zoo TV aesthetically, and as an art project it is a clearer thought." He later explained, "When that show worked, it was mindblowing." A highlight of the tour was the concert in Sarajevo where U2 were the first major group to perform there following the Bosnian War. Mullen described the concert as "an experience I will never forget for the rest of my life, and if I had to spend 20 years in the band just to play that show, and have done that, I think it would have been worthwhile." Bono called the show "one of the toughest and one of the sweetest nights of my life". One month after the conclusion of the PopMart Tour, U2 appeared on the 200th episode of the animated sitcom The Simpsons, "Trash of the Titans", in which Homer Simpson disrupted the band on stage during a PopMart concert.

"Reapplying for the job of the best band in the world" (2000-06)

Following the relatively disappointing reception of Pop, U2 declared they were "reapplying for the job ... the best band in the world". The group's tenth album, All That You Can't Leave Behind, was released in October 2000 and was produced by Brian Eno and Daniel Lanois. The record signaled a return to a more mainstream, conventional rock sound for the group mixed with the influences of their 1990s musical explorations. For many of those not won over by the band's 1990s music, it was considered a return to grace; Rolling Stone called it U2's "third masterpiece" alongside The Joshua Tree and Achtung Baby. The album debuted at number one in 32 countries, and its worldwide hit single, "Beautiful Day", earned three Grammy Awards. The album's other three singles, "Stuck in a Moment You Can't Get Out Of", "Elevation" and "Walk On", also won Grammy Awards.

For the Elevation Tour of 2001, U2 performed in a scaled-down setting, returning to arenas after nearly a decade of stadium productions. A heart-shaped ramp around the stage permitted greater proximity to the audience. During the tour, the group headlined a pair of Slane Concerts in Ireland, playing to crowds of 80,000. Following the September 11 attacks, All That You Can't Leave Behind found added resonance with audiences, and in October, U2 performed at Madison Square Garden in New York City for the first time since the attacks. Bono and the Edge later said these shows were among their most memorable and emotional performances. In February 2002, U2 performed during the halftime show of Super Bowl XXXVI and paid tribute to the victims of September 11. SI.com and Rolling Stone ranked their performance as the best halftime show in Super Bowl history.

U2's eleventh studio album, How to Dismantle an Atomic Bomb, was released in November 2004. The band were looking for a harder-hitting rock sound than All That You Can't Leave Behind. Thematically, Bono stated that "a lot of the songs are paeans to naiveté, a rejection of knowingness." The first single, "Vertigo", was featured in an internationally aired television commercial for the Apple iPod; a U2 iPod and an iTunes-exclusive U2 box set were released as part of a promotion with Apple. The album debuted at number one in the US, where first-week sales of 840,000 nearly doubled those of All That You Can't Leave Behind, setting a personal best for the band. Claiming it as a contender as one of U2's three best albums, Bono said, "There are no weak songs. But as an album, the whole isn't greater than the sum of its parts, and it fucking annoys me." The Vertigo Tour featured a setlist that varied more across dates than any U2 tour since the Lovetown Tour, and it included songs not played since the early 1980s. Like the Elevation Tour, the Vertigo Tour was a commercial success. The album and its singles won Grammy Awards in all eight categories in which U2 were nominated. In 2005, Bruce Springsteen inducted U2 into the Rock and Roll Hall of Fame. A 3-D concert film, U2 3D, filmed at nine concerts during the Latin American and Australian legs of the Vertigo Tour was released in theatres on 23 January 2008.

In August 2006, the band incorporated its publishing business in the Netherlands following the capping of Irish artists' tax exemption at €250,000. The Edge stated that businesses often seek to minimise their tax burdens. The move was criticised in the Irish parliament. The band defended themselves, saying approximately 95% of their business took place outside Ireland, that they were taxed globally because of this, and that they were all "personal investors and employers in the country". Bono would later say, "I think U2's tax business is our own business and I think it is not just to the letter of the law but to the spirit of the law."

No Line on the Horizon and U2 360° Tour (2006-2013)

Recording for U2's twelfth album, No Line on the Horizon, began with producer Rick Rubin in 2006, but the sessions were short-lived and the material was shelved. In June 2007, the band began new sessions with Brian Eno and Daniel Lanois, who contributed not only as producers, but for the first time with U2, as songwriters as well. In March 2008, the band signed a 12-year deal with Live Nation worth an estimated $100 million (£50 million), which includes Live Nation controlling the band's merchandise, sponsoring, and their official website. Recording on the album lasted through December 2008 in the US, the UK, Ireland, and Fez, Morocco, where the band explored North African music. Intended as a more experimental work than their previous two albums, No Line on the Horizon was released in February 2009 and received generally positive reviews, including their first five-star Rolling Stone review. Critics, however, did not find it to be as experimental as originally billed. The album debuted at number one in over 30 countries, but its sales of 5 million were seen as a disappointment by U2 standards and it did not contain a hit single.

The group embarked on the U2 360° Tour in June 2009. The concerts featured the band playing stadiums "in the round" on a circular stage, allowing the audience to surround them on all sides. To accommodate the stage configuration, a large four-legged structure nicknamed "The Claw" was built above the stage, with the sound system and a cylindrical, expanding video screen on top of it. At 50 meters (165 feet) tall, it was the largest stage ever constructed. The tour visited Europe and North America in 2009. At year's end, Rolling Stone named U2 one of eight "Artists of the Decade". The group's tours ranked them second in total concert grosses for the decade behind only the Rolling Stones, although U2 had a significantly higher attendance figure. They were the only band in the top 25 touring acts of the 2000s to sell out every show they played. U2 resumed the 360° Tour in 2010 with legs in Europe, Australia, and New Zealand. However, their scheduled headline appearance at the Glastonbury Festival 2010 and their North American leg that year were postponed following a serious injury to Bono's back. These appearances were rescheduled for 2011 after the South African and South American legs of the tour. By its conclusion in July 2011, U2 360° had set records for the highest-grossing concert tour with $736 million in ticket sales, and for the highest-attended tour with over 7.2 million tickets sold.

Following the release of No Line on the Horizon, U2 announced tentative plans for a follow-up record of songs from the album's sessions entitled Songs of Ascent. Bono described the project as "a meditative, reflective piece of work" with the theme of pilgrimage. However, the group could not complete it to their satisfaction, and ultimately it did not come to fruition. The band continued to work on other album projects, including a traditional rock album produced by Danger Mouse and a dance-centric album produced by RedOne and will.i.am.

Songs of Innocence and Innocence + Experience Tour (2013-present)

U2 suspended work on their next album late in 2013 to contribute a new song, "Ordinary Love", to the film Mandela: Long Walk to Freedom. The track, written in honour of Nelson Mandela, won the 2014 Golden Globe Award for Best Original Song. In November 2013, U2's long-time manager Paul McGuinness stepped down from his post as part of a deal with Live Nation to acquire his management firm, Principle Management. McGuinness, who had managed U2 for over 30 years, was succeeded by Guy Oseary. In February 2014, another new song, the single "Invisible", was debuted in a Super Bowl television advertisement and was made available in the iTunes Store at no cost to launch a partnership with Product Red and Bank of America to fight AIDS. Bono called the track a "sneak preview" of its pending record.

On 9 September 2014, U2 announced their thirteenth studio album, Songs of Innocence, at an Apple product launch event, and released it digitally the same day to all iTunes Store customers at no cost. The release made the album available to over 500 million iTunes customers in what Apple CEO Tim Cook called "the largest album release of all time." Apple reportedly paid Universal Music Group and U2 a lump sum for a five-week exclusivity period in which to distribute the album and spent $100 million on a promotional campaign. Produced by Danger Mouse with Paul Epworth, Ryan Tedder, Declan Gaffney and long-time collaborator Flood, Songs of Innocence recalls the group members' youth in Ireland, touching on childhood experiences, loves and losses, while paying tribute to musical inspirations. Bono described it as "the most personal album we've written." The record received mixed reviews and drew criticism for its digital release strategy; it was automatically added to users' iTunes accounts, which for many, triggered an unprompted download to their devices. The group's press tour for the album was interrupted after Bono was seriously injured in a bicycle accident in Central Park on 16 November 2014. Suffering fractures of his shoulder blade, humerus, orbit, and pinky finger, Bono said he was uncertain that he would ever be able to play guitar again.

In May 2015, U2 embarked on the Innocence + Experience Tour. Comprising 76 shows, the tour visited arenas in North America and Europe from May through December. The group structured their concerts around a loose narrative of "innocence" passing into "experience", with a fixed set of songs for the first half of each show and a varying second half, separated by an intermission-a first for U2 concerts. The stage spanned the length of the venue floor and was divided into three sections: a rectangular main stage, a smaller circular B-stage, and a walkway between them. A 96-foot-long double-sided video screen was suspended above and parallel to the walkway; the structure featured an interior catwalk between the screens, allowing the band members to perform amidst the video projections. U2's sound system was moved to the venue ceilings and arranged in an oval array, in hopes of improving acoustics by evenly distributing sound throughout the arena. In total, the tour grossed $152.2 million from 1.29 million tickets sold. The final date of the tour, one of two Paris shows rescheduled due to the November 2015 Paris attacks, was filmed for broadcast on the American television network HBO.

Musical style

Instrumentation

Since their inception, U2 have developed and maintained a distinctly recognisable sound, with emphasis on melodic instrumentals and expressive, larger-than-life vocals. This approach is rooted partly in the early influence of record producer Steve Lillywhite at a time when the band was not known for musical proficiency. The Edge has consistently used a rhythmic echo and a signature delay to craft his distinctive guitar work, coupled with an Irish-influenced drone played against his syncopated melodies that ultimately yields a well-defined ambient, chiming sound. Bono has nurtured his falsetto operatic voice and has exhibited a notable lyrical bent towards social, political, and personal subject matter while maintaining a grandiose scale in his songwriting. In addition, the Edge has described U2 as a fundamentally live band.

Despite these broad consistencies, U2 have introduced brand new elements into their musical repertoire with each new album. U2's early sound was influenced by bands such as Television and Joy Division, and has been described as containing a "sense of exhilaration" that resulted from the Edge's "radiant chords" and Bono's "ardent vocals". U2's sound began with post-punk roots and minimalistic and uncomplicated instrumentals heard on Boy and October, but evolved through War to include aspects of rock anthem, funk, and dance rhythms to become more versatile and aggressive. Boy and War were labelled "muscular and assertive" by Rolling Stone, influenced in large part by Lillywhite's producing. The Unforgettable Fire, which began with the Edge playing more keyboards than guitars, as well as follow-up The Joshua Tree, had Brian Eno and Daniel Lanois at the production helm. With their influence, both albums achieved a "diverse texture". The songs from The Joshua Tree and Rattle and Hum placed more emphasis on Lanois-inspired rhythm as they mixed distinct and varied styles of gospel and blues music, which stemmed from the band's burgeoning fascination with America's culture, people and places. In the 1990s, U2 reinvented themselves as they began using synthesisers, distortion, and electronic beats derived from alternative rock, industrial music, dance, and hip-hop on Achtung Baby, Zooropa, and Pop. In the 2000s, U2 returned to a more stripped-down sound, with more conventional rhythms and reduced usage of synthesisers and effects.

Lyrics and themes

U2's lyrics are known for their social and political commentary, and are often embellished with Christian and spiritual imagery. Songs such as "Sunday Bloody Sunday", "Silver and Gold", and "Mothers of the Disappeared" were motivated by current events of the time. The first was written about the Troubles in Northern Ireland, while the last concerns the struggle of a group of women whose children were killed or forcibly disappeared at the hands of the El Salvadoran government during the country's civil war. The song "Running to Stand Still" from The Joshua Tree was inspired by the heroin addiction that was sweeping through Dublin—the lyric "I see seven towers, but I only see one way out" references the Ballymun Towers of Northern Dublin and the imagery throughout the song personifies the struggles of addiction.

Bono's personal conflicts and turmoil inspired songs like "Mofo", "Tomorrow" and "Kite". An emotional yearning or pleading frequently appears as a lyrical theme, in tracks such as "Yahweh", "Peace on Earth", and "Please". Much of U2's songwriting and music is also motivated by contemplations of loss and anguish, coupled with hopefulness and resiliency, themes that are central to The Joshua Tree. Some of these lyrical ideas have been amplified by Bono and the band's personal experiences during their youth in Ireland, as well as Bono's campaigning and activism later in his life. U2 have used tours such as Zoo TV and PopMart to caricature social trends, such as media overload and consumerism, respectively.

While the band and its fans often affirm the political nature of their music, U2's lyrics and music have been criticised as apolitical because of their vagueness and "fuzzy imagery", and a lack of any specific references to actual people or characters.

Influences

The band cites The Who, The Clash, Television, Ramones, The Beatles, Joy Division, Siouxsie and the Banshees, Elvis Presley, Patti Smith, and Kraftwerk as influences. In addition, Van Morrison has been cited by Bono as an influence and the Rock and Roll Hall of Fame points out his influence on U2. U2 have also worked with and/or had influential relationships with artists including Johnny Cash, Green Day, Leonard Cohen, Bruce Springsteen, B.B. King, Lou Reed and Luciano Pavarotti.

Campaigning and activism

Since the early 1980s, the members of U2—as a band and individually—have collaborated with other musicians, artists, celebrities, and politicians to address issues concerning poverty, disease, and social injustice.

In 1984, Bono and Adam Clayton participated in Band Aid to raise money for the 1983-1985 famine in Ethiopia. This initiative produced the hit charity single "Do They Know It's Christmas?", which would be the first among several collaborations between U2 and Bob Geldof. In July 1985, U2 played Live Aid, a follow-up to Band Aid's efforts. Bono and his wife Ali, invited by World Vision, later visited Ethiopia where they witnessed the famine first hand. Bono would later say this laid the groundwork for his Africa campaigning and some of his songwriting.

In 1986, U2 participated in the A Conspiracy of Hope tour in support of Amnesty International and in Self Aid for unemployment in Ireland. The same year, Bono and Ali Hewson also visited Nicaragua and El Salvador at the invitation of the Sanctuary movement, and saw the effects of the El Salvador Civil War. These 1986 events greatly influenced The Joshua Tree album, which was being recorded at the time.

In 1992, the band participated in the "Stop Sellafield" concert with Greenpeace during their Zoo TV tour. Events in Sarajevo during the Bosnian War inspired the song "Miss Sarajevo", which premiered at a September 1995 Pavarotti and Friends show, and which Bono and the Edge performed at War Child. A promise made in 1993 was kept when the band played in Sarajevo as part of 1997's PopMart Tour. In 1998, they performed in Belfast days prior to the vote on the Good Friday Agreement, bringing Northern Irish political leaders David Trimble and John Hume on stage to promote the agreement. Later that year, all proceeds from the release of the "Sweetest Thing" single went towards supporting the Chernobyl Children's Project.

In 2001, the band dedicated "Walk On" to Burma's pro-democracy leader Aung San Suu Kyi. In late 2003, Bono and the Edge participated in the South Africa HIV/AIDS awareness 46664 series of concerts hosted by Nelson Mandela. The band played 2005's Live 8 concert in London. The band and manager Paul McGuinness were awarded Amnesty International's Ambassador of Conscience Award for their work in promoting human rights.

Since 2000, Bono's campaigning has included Jubilee 2000 with Bob Geldof, Muhammad Ali, and others to promote the cancellation of third-world debt during the Great Jubilee. In January 2002, Bono co-founded the multinational NGO DATA, with the aim of improving the social, political, and financial state of Africa. He continued his campaigns for debt and HIV/AIDS relief into June 2002 by making high-profile visits to Africa.

Product Red, a 2006 for-profit brand seeking to raise money for the Global Fund, was founded, in part, by Bono. The ONE Campaign, originally the US counterpart of Make Poverty History, was shaped by his efforts and vision.

In late 2005, following Hurricane Katrina and Hurricane Rita, the Edge helped introduce Music Rising, an initiative to raise funds for musicians who lost their instruments in the storm-ravaged Gulf Coast. In 2006, U2 collaborated with pop punk band Green Day to record a remake of the song "The Saints Are Coming" by The Skids to benefit Music Rising. A live version of the song recorded at the Louisiana Superdome was released on the single.

At the 3rd iHeartRadio Music Awards in April 2016, U2 were honored with the Innovator Award for "their impact on popular culture and commitment to social causes."

U2's and Bono's social activism have not been without its critics, however. Several authors and activists who publish in politically left journals such as CounterPunch have decried Bono for allowing his celebrity to be co-opted by an association with political figures such as Paul Wolfowitz, as well as his "essential paternalism". Other news sources have more generally questioned the efficacy of Bono's campaign to relieve debt and provide assistance to Africa. Tax and development campaigners have also criticised the band's move from Ireland to the Netherlands to reduce its tax bill.

Other projects

The members of U2 have undertaken a number of side projects, sometimes in collaboration with some of their bandmates. In 1985, Bono recorded the song "In a Lifetime" with the Irish band Clannad. The Edge recorded a solo soundtrack album for the film Captive in 1986, which included a vocal performance by Sinéad O'Connor that predates her own debut album by a year. Bono and the Edge wrote the song "She's a Mystery to Me" for Roy Orbison, which was featured on his 1989 album Mystery Girl. In 1990, Bono and the Edge provided the soundtrack to the Royal Shakespeare Company London stage version of A Clockwork Orange (one track, "Alex Descends into Hell for a Bottle of Milk/Korova 1", was on the b-side to "The Fly" single). That same year, Mullen co-wrote and produced a song for the Republic of Ireland national football team in time for the 1990 FIFA World Cup, called "Put 'Em Under Pressure", which topped the Irish charts for 13 weeks.

Together with the Edge, Bono wrote the song "GoldenEye" for the 1995 James Bond film GoldenEye, which was performed by Tina Turner. Clayton and Mullen reworked the "Theme from Mission: Impossible" for the franchise's 1996 film. Bono loaned his voice to "Joy" on Mick Jagger's 2001 album Goddess in the Doorway. Bono also recorded a spare, nearly spoken-word version of Leonard Cohen's "Hallelujah" for the Tower of Song compilation in 1995. Additionally, in 1998, Bono collaborated with Kirk Franklin and Crystal Lewis along with R. Kelly and Mary J. Blige for a successful gospel song called "Lean on Me".

Aside from musical collaborations, U2 have worked with several authors. American author William S. Burroughs had a guest appearance in U2's video for "Last Night on Earth" shortly before he died. His poem "A Thanksgiving Prayer" was used as video footage during the band's Zoo TV Tour. Other collaborators include William Gibson and Allen Ginsberg. In early 2000, the band recorded three songs for The Million Dollar Hotel movie soundtrack, including "The Ground Beneath Her Feet", which was co-written by Salman Rushdie and motivated by his book of the same name.

In 2007, Bono appeared in the movie Across the Universe and performed Beatles songs. Bono and the Edge also wrote the music and lyrics for the Broadway musical Spider-Man: Turn Off the Dark. Additionally, the Edge created the theme song for Season 1 and 2 of the animated television series The Batman.

Legacy

U2 have sold more than 150 million records as of 2010, placing them among the best-selling music artists in history. With 52 million certified units by the RIAA, U2 rank as the 21st-highest-selling music artist in the US. The group's fifth studio album The Joshua Tree is one of the best-selling albums in the US (10 million copies shipped) and worldwide (25 million copies sold). Forbes estimates that U2 earned US$78 million between May 2011 and May 2012, making them the fourth-highest-paid musical artist. According to Billboard Boxscore, the band grossed $1.67 billion in ticket sales from 1990 to 2016, second only to the Rolling Stones. The Sunday Times Rich List 2013 estimated the group's collective wealth at €632,535,925.

Rolling Stone placed U2 at number 22 on its list of the "100 Greatest Artists of All Time", while ranking Bono the 32nd-greatest singer and the Edge the 38th-greatest guitarist. In 2004, Q ranked U2 as the fourth-biggest band in a list compiled based on album sales, time spent on the UK charts, and largest audience for a headlining show. A 2011 readers' poll in Q named U2 the Greatest Act of the Last 25 Years. VH1 placed U2 at number 19 on its 2010 list of "The 100 Greatest Artists of All Time". In 2010, eight of U2's songs appeared on Rolling Stone's updated list of "The 500 Greatest Songs of All Time", with "One" ranking the highest at number 36. Five of the group's twelve studio albums were ranked on the magazine's 2012 list of "The 500 Greatest Albums of All Time"—The Joshua Tree placed the highest at number 26. Reflecting on the band's popularity and worldwide impact, Jeff Pollack for The Huffington Post said, "like The Who before them, U2 wrote songs about things that were important and resonated with their audience".

U2 received their first Grammy Award in 1988 for The Joshua Tree, and they have won 22 in total out of 34 nominations, more than any other group. These include Best Rock Duo or Group, Album of the Year, Record of the Year, Song of the Year and Best Rock Album. The British Phonographic Industry has awarded U2 seven BRIT Awards, five of these being for Best International Group. In Ireland, U2 have won 14 Meteor Awards since the awards began in 2001. Other awards include one AMA, four VMAs, eleven Q Awards, two Juno Awards, three NME Awards, and two Golden Globe Awards. The band were inducted into the Rock and Roll Hall of Fame in early 2005. In 2006, all four members of the band received ASCAP awards for writing the songs, "I Still Haven't Found What I'm Looking For" and "Vertigo".

Members

Principal members

• Bono - vocals, rhythm guitar, harmonica
• The Edge - lead guitar, keyboards, vocals
• Adam Clayton - bass guitar
• Larry Mullen, Jr. - drums, percussion

Early members

• Dik Evans - guitar
• Ivan McCormick - guitar

Discography

Studio albums

• Boy (1980)
• October (1981)
• War (1983)
• The Unforgettable Fire (1984)
• The Joshua Tree (1987)
• Rattle and Hum (1988)
• Achtung Baby (1991)
• Zooropa (1993)
• Pop (1997)
• All That You Can't Leave Behind (2000)
• How to Dismantle an Atomic Bomb (2004)
• No Line on the Horizon (2009)
• Songs of Innocence (2014)

Concert tours

Dennis Sheehan was U2's tour manager for over 30 years until his death in May 2015.

• U2-3 Tour (1979-1980)
• 11 O'Clock Tick Tock Tour (1980)
• Boy Tour (1980-1981)
• October Tour (1981-1982)
• War Tour (1982-1983)
• The Unforgettable Fire Tour (1984-1985)
• The Joshua Tree Tour (1987)
• Lovetown Tour (1989-1990)
• Zoo TV Tour (1992-1993)
• PopMart Tour (1997-1998)
• Elevation Tour (2001)
• Vertigo Tour (2005-2006)
• U2 360° Tour (2009-2011)
• Innocence + Experience Tour (2015)