Crosby, Stills, Nash and Young's 1974 tour is one of the most notoriously coked-fueled tours in rock history. All four of them were doing insane amounts of the stuff, and the shows suffered as a result. The tour was largely confined to America, but it wrapped up at London's Wembley Stadium on September 14th, 1974. Stephen Stills was so far gone at this point that he reportedly believed that he fought in Vietnam, signing autographs "Stephen Stills, U.S. Marine Corps." The Wembley show was filmed for posterity and it recently popped up on YouTube.
"Everybody was so heavy into the cocaine trip, and that stuff [that was copped had] to be cut with borax," tour guest Joni Mitchell said. "People were shovelin' it in and you couldn't get high off it. Before we went on, everybody had nosebleeds."