Umm guys? How to dismantle an atomic bomb? Cancer.
The Unforgettable Fire refers to a painting done by a survivor of the nuclear bombing of japan
The Joshua Tree is a type of tree in the southwest USA which was a major inspiration for the making of that album.
Rattle & Hum is a lyric from Bullet The Blue Sky, and also the sounds of a tour
Achtung means Warning in German; The album was largley made there when the world was drastically changing. The Berlin wall had fallen, The Soviet Union was westernizing and the rest of Europe was uniting into one power. Watershed times. And U2 was saying, great! But lets just be careful about all this.
Zooropa - A name given to the second european leg of the Zoo TV tour. Zoo comes from Zoo Station, at the time of the album, the only rail station in West Berlin and also the only way to get to East Berlin. Zooropa became an eponymous term to mean the Achtung Baby industrial sound, fused with the then current sounds of european pop and r&b.
Passengers - Larry didn't want this to be a full U2 album so they choose this as the name of the band due to the amount of extra named muscians that took part in the project. They decided they would create a compilation of soundtracks to ficticious movies. And thus "Original Soundtracks".
Pop - Pop was named thusly because of the resurgence at the time of pop culture and pop music primarily. Remember this was 1997 and alternative though while dying, was still king in rock. Pop as an album was to be diverse as pop as a cultural entity; combinging disco, rock, techno, retro and r&b.
All That You Can't Leave Behind - If taken literraly from Walk On; it means to take everything that's important to you and leave it behind so it doesn't drag you down - everything materialistic, earthly. The goal is soul.
How to dismantle an atomic bomb - like the best U2 lyrics, or albums; even their own name; it has a double meaning. How To Dismantle An Atomic Bomb? Well given all the heart iconography surrounding the album, I'd have to say it's with love. And this seems relevent given the worlds current political climate. Now apparently Bono says that his father was an Atomic Bomb. How was he dismantled? Cancer. And the album is about the day after so to speak.
The Buffalo on the Best Of 2. To kill a lot of Buffalo at once, American Indians use to stampede them off a cliff. They got them all worked up and run to their unknowing death. A homosexual artist with aids created a paintin depicting this masacre and drew comparisons with the aids crisis. U2 made the painting the cover to the One single. They created animations of this painting and put them up on the screens of the Zoo TV tours and (I think; not sure) the Pop tours. It became one of the defining images of their ninties work.