Between 1946 and 1958, the United States detonated 67 nuclear bombs in their Pacific Proving Grounds on, in, and above Bikini and Enewetak Atolls in the Marshall Islands, a part of the United Nations Pacific Trust Territories. Hydrogen bombs, especially the March 1, 1954 Bravo test, were immensely destructive. Visible from 250 miles with a mushroom cloud stretching 60 miles across, Bravo vaporized several small islands, left a mile-wide crater on the atoll, and generated heavy radioactive fallout across a 50,000 square mile area.