Released under the name Passengers, Original Soundtracks is easily the most marginal album included on this list — so much so that most casual fans are probably entirely unaware that it even exists. With Brian Eno fulfilling a more extensive collaborative role, the album features U2 playing with loops and soundscapes, positioning the album as a set of songs soundtracking imaginary movies (except for a handful that were attached to real films). Very much a transitional, experimental effort, Original Soundtracks 1 received more mixed reactions from fans and critics alike, and in hindsight some of this is understandable. Some of the more ambient tracks — namely “One Minute Warning,” “Plot 180,” and “United Colours” — feel very dated, like the sort of things you’d hear in forgotten ’90s action movies or now associate with an aged video game. Others have fared better. “Always Forever Now” could’ve been a great segue track had U2 recorded a full album between Zooropa and Pop and “Corpse (These Chains Are Way Too Long),” one of few tracks to feature vocals, beat Radiohead to the Hail to the Thief punch by eight years, and is an interesting oddity for U2. Mainly, though, a lot of it really does feel minor and as if the band were just trying some things out. The fact that some of it just sounds so old really hinders it, considering how well most of the band’s other work has aged. Oddly, Zooropa, which also dabbled in ’90s electronic music, still sounds great. Original Soundtracks 1 almost sounds like it preceded that album.

While there’s no way getting around the Passengers detour’s status as a curiosity, the main reason I included it on this list at all was to bring attention to some of the best U2 songs you (might) have never heard of. Out of the more traditional songs, “Miss Sarajevo” is by far the most recognizable, having lived on in their live shows and becoming a classic ’90s U2 track. The real hidden gems on Original Soundtracks 1 are “Slug” and “Your Blue Room.” The former is unlike anything else the band ever recorded, even on their most electronic-based detours on Zooropa or Pop. It fades in, unwavering on a bed of synthesized tribal rhythms and celestial synthesizers. Bono only comes in almost two full minutes in, and amongst the haunting serenity of the song’s currents, calmly walks through a list of confessions about what he doesn’t want. It’s perfect for driving on the highway late at night, it’s perfect for walking down a LCD-drenched street in the early morning, and if in my lifetime they get that whole commercial space flight thing going, it’s the song I’d listen to as we exit the atmosphere.

Then there’s “Your Blue Room” which is just… well, it’s not a well-known U2 song, but I feel like there’s a small corner of the fanbase that knows it and loves it all the more fiercely with the knowledge that it’ll go on being so under-appreciated in the grand scheme of U2’s work. I can’t entirely explain why it has the effect it does. The most distinctive elements of “Your Blue Room” are an organ figure and Mullen’s drum pattern, neither of which vary much through the song. Bono spends the song alternating between his rich lower register and falsetto. All the little pieces that make up “Your Blue Room” seem simple enough, and yet it doesn’t sound like 1995, nor does it really sound like any other year. It doesn’t sound like U2’s other work either, and it’s hard to think of a band it does sound like. It seems to exist entirely outside most of their music. With their whole stockroom of affecting ballads and anthems alike, they never got as subtly beautiful and devastating as on “Your Blue Room.” On one hand it makes you wonder what Original Soundtracks 1 could’ve sounded like as a full-fledged U2 album, what form that 1995 hinge point between Zooropa and Pop would’ve taken. In the absence of such a thing, “Your Blue Room” is all the more powerful for the way it stands out without any real context, utterly singular.