Writing and recording
Following difficult recording sessions at Hansa Studios in Berlin in late 1990, U2 undertook the second phase of the recording sessions for Achtung Baby in Dublin. They struggled with the song "Lady With the Spinning Head" (later released as a B-side), but three separate tracks, "Zoo Station", "Ultraviolet (Light My Way)" and "The Fly", were derived from it. The band ultimately decided to take "Zoo Station" in a more industrial direction than "Lady With the Spinning Head".
Berlin Zoologischer Garten railway station, colloquially called Bahnhof Zoo ("Zoo Station") in Germany, partially inspired the song's lyrics.
"Zoo Station" came together near the end of the recording sessions when audio engineer Flood was mixing the song and introduced distortion to the drums. The song's direction was largely influenced by the production team of Daniel Lanois, Brian Eno, and Flood. Lead vocalist Bono had been disappointed with his vocals from early recording sessions for the album and told the production team, "Let's just try something that's gonna put me in a completely different place". After they distorted his voice to make it sound as if it were coming from a megaphone, Bono was inspired to sing in a persona, as the effect gave his vocals a different "emotional feel". Flood mixed the final track with the assistance of Shannon Strong. Along with Robbie Adams, Strong also assisted Flood with engineering. Lanois provided additional guitar during recording.
With Achtung Baby, the group sought to recover some of the Dadaist characters and stage antics they had dabbled with in the late 1970s as teenagers. U2 had abandoned these ideas for more literal themes in the 1980s. However, for the new album, the band was interested in no longer making obvious sense. Accordingly, the lyrics for "Zoo Station" were inspired by the surrealism of a story about Berlin during World War II that Bono heard. Animals escaped the city's zoo after it was damaged in overnight bombing, and as a result, rhinoceroses, pelicans and flamingoes wandered around the next morning while people were sifting through the rubble. Bono was also inspired by Berlin Zoologischer Garten railway station, also known as "Zoo station", previously the main railway station in West Berlin. The station was notorious as a haunt for drug dealers, prostitutes and pimps, pick-pockets and transients, particularly prior to German reunification, when it was run by the East German railway. He compared the song to the station, saying "it was written as an opening track, the beasts breaking out of their cages", and was interested in using the zoo as a metaphor and he took further inspiration from the subway station representing Europe at a crossroads.
During recording, Eno created several prototype mixes of the song. The Edge recalled how these different mixes assisted the band in creating the final version of the track. One of these early versions was later released under the title "Bottoms (Watashitachi No Ookina Yume)" as a bonus track on the UK and Japanese promotional releases of the experimental 1995 album Original Soundtracks 1 by Passengers, a side project by U2 and Eno, as well as a B-side on some versions of the "Miss Sarajevo" single. "Bottoms (Watashitachi No Ookina Yume)" is an instrumental track and was described by The Edge as a "crazy" mix. He added "'Bottoms' was done in Japan, and we just built on that mix. Sometimes you can end up with something completely distinctive."
Although "Zoo Station" was not released as a single, it was included on a 12-inch promotional recording to promote U2's Zoo TV Tour in North America, along with studio and remix versions of "Lady with the Spinning Head".