The Ramones on the 4th of July, 1976
http://www.ijamming.net/?p=1037

The Ramones' debut British show, at the Roundhouse, on the convenient date of July 4, 1976 – the USA's Bicentennial. The Ramones' performance that night has been cited over the years as a crucial moment in the development of punk rock, especially as members of the Damned, Clash and Pistols were all in the audience.