Fifty years ago today, the United States entered an unfamiliar territory known as the nuclear test moratorium.
President Dwight Eisenhower halted all nuclear testing for one year, beginning Oct. 31, 1958. It was the first significant step back from an arms race that had taken on a new dimension in the era of the hydrogen bomb, a thousand times more powerful than the weapon used on Hiroshima at the end of World War II.
The moratorium, with extensions and a frightening intermission that included the Cuban Missile Crisis, led to the end of atmospheric testing in the world.