Operation Castle

Shot Koon. Yield of 110 kilotons using a a thermonuclear device designed at the University of California Radiation Laboratory (UCRL). The test was a “fizzle,” resulting in substantially less than the predicted 1 megaton. Still, this “fizzle” was enough to gouge a crater 990 feet wide and 75 feet deep, as can be seen in the before and after map above. A successful shot would’ve obliterated most of the island. Bikini Atoll, 7 April 1954

Shot Union. Yield of 6.9 megatons using a TX-14 thermonuclear device, one of the first deployable U.S. thermonuclear bombs. The yield was somewhat higher than the predicted 3-4 megatons. Although the barge had been moored in over 160 feet (49 m) of water, the test left a crater 3,000 feet (910 m) in diameter and 90 feet (27 m) deep in the bottom of the lagoon. Bikini Atoll, 26 April 1954

Shot Yankee 2. Yield of 13.5 megatons using a Mk-25 thermonuclear device, one of the largest and most powerful nuclear weapons deployed by the US. Like with Union and Bravo, Yankee exceeded the predicted yield of 10 megatons. This was the second-largest nuclear test the US would conduct. Bikini Atoll, 5 May 1954