When We Tested Nuclear Bombs

In Focus has photos from When We Tested Nuclear Bombs "Since the time of Trinity -- the first nuclear explosion in 1945 -- nearly 2,000 nuclear tests have been performed, with the majority taking place during the 1960s and 1970s. When the technology was new, tests were frequent and often spectacular, and led to the development of newer, more deadly weapons. But starting in the 1990s, there have been efforts to limit the future testing of nuclear weapons, including a U.S. moratorium and a U.N. comprehensive test ban treaty. As a result, testing has slowed -- though not halted -- and there are questions about the future. Who will take over for those experienced engineers who are now near retirement, and should we act as stewards with our enormous stockpiles of nuclear weapons? Gathered here are images from the first 30 years of nuclear testing. See also 'Can We Unlearn the Bomb?' and 'Atomic Weapons on Film.' [36 photos]"