NASA's prototype space shuttle orbiter, Enterprise, is hauled from the processing hangar built on north Vandenberg across the hilly terrain to Space Launch Complex-6 for attachment to the waiting tank and boosters. SLC-6 was built to provide a West Coast shuttle launch pad, but the program was cancelled after the Challenger accident. This stacking of Enterprise was the only time a shuttle stood on SLC-6.
Source: Air Force (2 min 39 sec QuickTime 6 file)
Download this clip to your hardrive.
(Windows users right-click this link. Mac users control-click this link)