When you're as big as U2, you can get away with basically whatever you want -- and when it came to making albums in the mid-'90s, what Bono and the boys wanted to do was electronic music. Their 1991 release 'Achtung Baby' had some elements of the genre, but on 'Pop,' they went all in, mostly ditching their guitars and acquiring a mountain of synths, sequencers and drum machines -- all in the name of forcing themselves out of their comfort zones.

It definitely worked. 'Pop' ranks among their most ambitiously experimental and eclectic releases to date, touching on everything from techno, dance and even industrial music. With its digitized beats and samples, lead single 'Discotheque' was a bold introduction to the new U2 sound.

Watch U2 Perform 'Discotheque' in Mexico City