On August 6 and 9, 1945, U.S. airmen dropped the nuclear bombs Little Boy and Fat Man on the Japanese cities of Hiroshima and Nagasaki. On April 26, 1986, the number four reactor at the Chernobyl Nuclear Power Plant in the Ukraine exploded.
Everyone's got a notion of how the last century went, in terms of nuclear explosions. There was Hiroshima, then Nagasaki. There were some nuclear tests out in the desert, and the ocean. But would you believe there've been over 2000?