The document summarizes the key events of the Cold War nuclear arms race between the United States and Soviet Union. It began after WWII when the US created the first atomic bomb and used it against Japan. The Soviets tested their first bomb in 1949, starting a nuclear arms competition. Both countries developed more powerful hydrogen bombs and delivery systems like ICBMs throughout the 1950s and 60s. Arms control treaties in the late Cold War aimed to limit nuclear stockpiles and curb proliferation.