An underwater nuclear test being conducted during Operation Dominic, Pacific Coast off California; ca. May 11th 1962

Imagine the sonar shock animals would have received from these!!! (I’m not a scientist, smart person or even reasonably clever in any way…..But, by the size of that blast wave you would have to image the absolute sheer devastation of all aquatic life within a few hundred yards…also any sea creature that depends on gentle clicks and soft squeaks would have been seriously annihilated or needed at least 300 ibuprofens.)
This isn’t even the impressive part. The impressive part comes right afterwards…
Watch this video of the explosion:
Crossroads Baker nuclear explosion of July 25, 1946, test fired at 27m underwater. Photo taken from a tower on Bikini Island, 3.5 mi (5.6 km) away.

There is controversy over the black splotch in the lower right corner of the blast whether it is the battleship Arkansas (which weighed 26,000 tons and was 562 feet long) or if its smoke from the detonation.
This is a picture from the 1946 detonation of a 23 kiloton nuclear bomb (same device design that was used to bomb Nagasaki) during operation Crossroads in Bikini Atoll in the Pacific. This tests was designated Baker denoting that it was the second in the series of 3 planned tests (but only two were carried out. The first being Able). It was the 3rd nuclear test ever conducted, and the 5th nuclear explosion in history.
The bomb was detonated 90 feet underwater amidst a fleet of decommissioned US and seized Japanese vessels. It was meant to simulate and document the effects of nuclear weapons in naval warfare.