In 1954, a U.S. Air Force B-57B Canberra aircraft filmed Castle Bravo, the most powerful nuclear test ever carried out by the United States. The detonation took place at Bikini Atoll in the Marshall Islands and produced a fifteen megaton explosion that was about one thousand times stronger than the bomb dropped on Hiroshima. The fireball grew several miles wide, and the mushroom cloud rose more than forty miles into the sky. The unexpected strength of the blast spread dangerous radioactive fallo

In 1957, the United States conducted its first underground nuclear test, known as Rainier, at the Nevada Test Site. The device was detonated inside a carved tunnel deep within the rock, marking a major shift from open-air tests to underground experiments that produced far less radioactive fallout. The explosion created a powerful seismic wave that scientists used to study how nuclear blasts behave beneath the earth. via: NNSANevada yt | History In Pictures