In November 1945, just a few months after atomic bombs were dropped on the Japanese cities of Hiroshima and Nagasaki at the end of WW II, U.S. military leaders began planning additional nuclear weapons tests. The first location that they picked to stage a blast was a remote place that probably few Americans ever knew existed. Bikini Atol, a tiny ring of small coral islands, with a total mass of only about two square miles, was part of the larger Marshall Islands chain in the central Pacific Ocean. Between 1946 and 1958, the U.S. detonated 23 nuclear devices at Bikini Atoll. Among those were twenty airborne tests of hydrogen bombs, dropped over the tiny island of Namu 66 years ago on 21 May. The powerful blast created a fireball at least four miles wide and brighter than 500 suns. For the good of mankind , Commodore Ben H. Wyatt, military governor of the Marshall Islands, told them the tests were necessary to prevent future wars. The Atoll was picked as the location for Operation Crossroads, a program to investigate the effects of nuclear blasts on Navy vessels. A target fleet of 95 ships was positioned in Bakini Atol's Lagoon, with laboratory animals - pigs, goats, and mice-onboard so that scientists could study the potential effects of radiation on ship crews. A support fleet of another 150 ships withdrew to a position ten nautical miles from the Atoll, and waited. After the 1946 tests, Bikini Atoll wasn't used again as a aite until 1954, when the U.S. began to test hydrogen bombs. In 2010, UNESCO declared Bikini Atoll a World Heritage site-As a reminder of the fearsome power of nuclear weapons and their influence on modern civilization.