Kottke wrote: "2153! I had no idea there had been that much testing. According to Wikipedia, the number is 2119 tests, with most of those coming from the US (1032) and the USSR (727). The largest device ever detonated was Tsar Bomba, a 50-megaton hydrogen bomb set off in the atmosphere above an island in the Barents Sea in 1961. Tsar Bomba had more than three times the yield of the largest bomb tested by the US. The result was spectacular."
Orbital Mechanics made this: