1. Queen and David Bowie, "Under Pressure"
In July 1981, David Bowie headed over to Montreux's Mountain Studio to record a track with Queen. He originally planned on singing on "Cool Cat," but the session didn't gel. Luckily, the four members of Queen and Bowie started jamming on a new piece that soon morphed into "Under Pressure." The whole thing came together within a matter of hours, though there's a dispute to this day over who exactly came up with the iconic bass line. The song became a worldwide hit, though the never performed it together live — even though Bowie's set immediately followed Queen's at Live Aid.