"Epic" compositions worth giving a spin


Not concept albums, but a single LP side consisting of a work with some sort of unity/continuity.  Possibly with one or more recurring musical themes or ideas.  Could be vocal or pure instrumental and I would think in the 20-30 minute duration.  What made me think of this is "Supper's Ready," by Genesis, which I've listened to a few times recently.  It seems challenging to put together a piece that has repetition and variety such as this and I think they pulled it off nicely.  I especially like the concert version with the added visual interest of Peter Gabriel's costumes, gestures and mime routines, but for me this one works well with just the music.  Does anyone have a favorite one-side long-form piece to throw out?
128x128tostadosunidos
"A Plague of Lighthouse Keepers". Van Der Graff Generator
"Remember the Future" and "A Tab in the Ocean". Nektar
"Eruption". Focus
"Close to the Edge" Yes
"Arriving Somewhere But Not Here". Porcupine Tree
"Dabsong Concerto". And "Nine Feet Underground" Caravan
"The Snow Goose" Camel
"The Magicians Birthday".  Uriah Heep
"Child in Time" and "Space Truckin"  from Deep Purple "Made in Japan"
"Tarkus" and "Karn  Evil 9" by ELP
"The Soft Parade" The Doors
"Terrapin Station". Grateful Dead
"Thick as a Brick" and Minstrel in the Gallery". Jethro Tull
"Dogs" Pink Floyd



I am working my way through the symphonies of Sir Arnold Bax on the Lyrita label. They certainly qualify!
How about Miles Davis:  "Bitches Brew" (the track, on the LP of the same name) and "Right Off" (side 1 of "A Tribute to Jack Johnson"). 
Rodney Crowell: The Houston Kid; Rosanne Cash: The List; Iris Dement: The Trackless Woods; Loudon Wainwright III: Last Man on Earth; The Fraternal Order of the All (Andrew Gold and Graham Gouldman): Greetings From Planet Love; Bill Frisell: The Space Age!; Evan Johns: Moontan; The Ventures: In Space; Bob Dylan: Blood On The Tracks and/or Self Portrait; The Band: Music From Big Pink; The Band: The Band; The Beach Boys: Pet Sounds and/or Smile; Van Dyke Parks: Song Cycle; Randy Newman: Good Old Boys; Neil Young: Harvest; The Traveling Wilburys: Vol.1; The Rutles: The Rutles.