Don't laugh. The December issue of Antiquity - a quarterly review of world archaeology - contains an article by Paul Graves-Brown and John Schofield: The filth and the fury: 6 Denmark Street (London) and the Sex Pistols (title link). Catchy title. The authors put forward the notion that graffiti by Sex Pistols frontman Johnny Rotten in 1975 makes the flat the group stayed in an important historical and archaeological site. They claim this is "a direct and powerful representation of a radical and dramatic movement of rebellion". I'll stick with cave art, thanks; it's more sophisticated, more artistic and more interesting. The graffito above shows Rotten's rotten tooth. His real name was John Lydon.