The Who live at Live Aid (partially lost concert footage; 1985)
Live Aid was a music festival aiming to raise relief money to help the 1984 famine in Ethiopia, featuring notorious artists such as David Bowie, Elton John, Led Zeppelin, Paul McCartney and The Who.
As the festival suffered from technical issues, a power failure in the middle of The Who's performance of "My Generation" resulted in the loss of both the video and main audio feeds user for television broadcast, while many US radio stations relied on broadcasting a lower quality mirror feed after the cut.
The backup still took a few seconds to set up and, due to technical limitations, it took several seconds for the radio signal to cross the Atlantic, resulting in a small portion of the audio and a large portion of the video remaining lost to this day.