Ever since WWII, advances in nuclear warfare gained attention. The US and Russia were in a nuclear arms race because of the Cold War between the two. Well-known tests occurred at the Bikini Atoll near Hawaii. Operation crossroads was one such test, and the is a famous picture of it as a giant cloud of vapor and splashing water dwarfing huge battleships which look like little ants! There were two detonations yielding 23 kilotons on July 1, 1946. The first only destroyed 5 ships (Pretty impractical for a nuclear weapon!), but the second was done underwater and destroyed more. The explosion raised the seawater temperature to 99,000 degrees Fahrenheit! Another major test was the Castle Bravo test. It was detonated at dawn on March 1, 1954. It’s well-known because it yielded 15 megatons but was only supposed to yield 4 to 8 and ended up being 1000 times more powerful than the bombs at Hiroshima and Nagasaki! The test ended up contaminating islands owned by the US and the military crew got radiation sickness and had to shelter in place. Inhabitants on the island also fell ill and the US was accused of using them for experimentation. The fallout even spread to Japan, Australia India and parts of Europe! For the record, the most powerful Nuclear explosion (The Tsar Bomba Царь-бомба) was created by the Soviets yielding 50 megatons! Because of incidents like Castle Bravo, today Nuclear testing is banned in the sea and atmosphere. Probably a good idea!
(Bravo mushroom cloud, Tsar Bomba, and scale of sizes)