Shattered battleships. Blasted aircraft carriers. It was a startling outcome that terrified the United States Navy. Now footage of the final death throes of the battle fleet assembled at Bikini Atoll atomic bomb test of 1946 has been released.
The US National Security Archives has declassified and released the entire stock of footage shot by surveillance aircraft that over flew the nuclear test site just minutes after the bomb went off.
It shows a churning cauldron at the bottom of the coral bay where the device was detonated, and a slew of major warships battered into hulks - and many of them sinking.
The test had been named Operation Crossroads.
It proved to be just that.
The US Navy had wanted to find out what atomic blasts could do to its heavily protected warships. So it positioned 95 war surplus ships in a neat array around the lagoon.
It expected to be able to knock out a few dents, give them a wash and to tow the ships away for further experimentation.
What it got was a horrifying demonstration of the brutal power of the bomb - and the lingering poison of nuclear fallout.
The first bomb - code name 'Able' - was similar to the one used on Nagasaki in Japan.
The 23 kiloton device exploded 160m above the surface and only sank a handful of relatively minor ships. The radiation (which had spiked to lethal levels within the ships) quickly dissipated in days.
But the second bomb - code name 'Baker' - proved to be a real shock.
Set off some 30m beneath the surface on July 25, 1946, it hurled an enormous dome of water vapour across the surface and a shock wave through the water that simply hammered the fleet to destruction.
Two heavily armoured battleships and an enormous aircraft carrier soon sank, much to the US Navys' surprise. Five other big ships also went down.
But the true shock was the radiation.
Mountains of radioactive water, dirt and debris had been hurled into the sky and dumped back in the lagoon, inundating the ships.
It proved impossible to decontaminate the vessels of this fallout. In fact, the navy soon found itself in crisis as the crews sent to assess and reactivate the ships quickly became exposed.
Some 200 pigs had been placed at different positions within the ships as part of the test. They were all dead within a month.
The lingering nature of the fallout had simply not been expected.
The hulks of the ships had to be deliberately sunk because they remained too dangerous to be used in any way again.