One of the biggest bands in the world today, U2 have in fact been that way for over 2 decades, as shown when they were one of the star acts at Live Aid of 1985, and opened this year's Live 8 extravaganza along with former Beatle Paul McCartney. Although they have been frequently criticized for what some sections of the music media deem to be excessively pompous political posturing, they have made some truly exceptional albums, including 1987's "The Joshua Tree", which many fans consider to show the band at their stadium rock best.
During the 1990s they changed their sound following criticism of their "Rattle And Hum" album. While these changes resulted in "Achtung Baby", an album that frequently gets cited as one of the best of the 1990s, efforts such as "Pop" and "Zooropa" were greeted with a muted critical reception, and since the turn of the century, U2 have gone back to their original sound, with the releases of "All That You Can't Leave Behind" and "How To Dismantle An Atomic Bomb". Few would bet against their continued future success.
