Complex sentence: With absolutely no knowledge of the effects of radiation, the young men played war games, sometimes less than 1,000 yards away from exploding nuclear weapons--bombs as much as four times more powerful than the bomb dropped on Hiroshima on August 6,1945.
Split into simpler sentences: With absolutely no knowledge of the effects of radiation, the boys played "war games", sometimes less than 1 000 yards away from exploding nuclear bombs. Bombs as much as four times more powerful than the bomb dropped on Hiroshima on August 6,1945.