The shallow wreck site of the Liberty ship , the Richard Montgomery.
Contained over seven thousand tons of explosives, the Richard Montgomery, grounded and sank on the 20th August 1944, off Sheerness Middle Sand in about 33ft of water at low tide.
Although part of the cargo was salvaged, 3,173 tonnes were left aboard; enough, that if the ship were to blow up, it would be the largest non-nuclear explosion in history. Sheerness and the nearby oil refinery on the Isle of Grain be swamped by a huge tidal wave.
The wreck continues to pose a threat to navigation over 60 years later.