Pink Floyd/WMG

Ummagumma is a concept album
Ummagumma is widely known to Floyd fans to be slang for sex, and what is Ummagumma, but Ummagumma? Disk 2 of the album contains experimental solo projects from each member. On disk 1 of the album, we hear the band come together live playing extended takes of four of their songs, clearly an appropriate metaphor for an auditory foursome.

"A Saucerful of Secrets" even ends with Gilmour passionately moaning the vocal parts of the song, parts which were earlier played by a ghostly-sounding orchestra on the album which shares the song's title.

Pink Floyd's "Wish You Were Here" is about the Museum Fremen in God Emperor of Dune.
God Emperor of Dune is set thousands of years after the first three Dune books. The planet Rakis (formerly known as Arrakis) has become a lush paradise, although a small region is preserved as desert, and a small group of descendants of the Fremen still practice the old ways. They are considered more of a curiosity and a tourist attraction than anything and are now known as "Museum Fremen." The second verse of "Wish You Were Here" describes them perfectly: ""Did they get you trade Your heroes for ghosts Hot ashes for trees Hot air for a cool breeze Cold comfort for change? Did you exchange a walk-on part in the war for a lead role in a cage?""

Since "Wish You Were Here" came out a few years before God Emperor of Dune, Pink Floyd is also capable of time travel.


 * Actually, these lines were references to Syd Barrett's solo works.

Wish You Were Here is a concept album about Syd Barrett.
It...it is.