Most explosive shipwreck

Built in 1943, the SS Richard Montgomery was a "Liberty Ship", a class of cargo ship built in the USA during WWII to carry large numbers of troops and material. In 1944, she was bound to the UK with a cargo of 6,225 tonnes (6,860 US tons) of munitions but sank while anchored in the Thames Estuary off Kent, UK, on 25 August 1944. Some of the cargo was salvaged but an estimated 1,400 tonnes (1,540 US tons) remain on the wreck site to this day, which lies in a protected exclusion zone marked with buoys.

The vessel anchored in the Nore sandbank off Sheerness, Kent, UK, but dragged its anchor and grounded (on 20 August 1944), causing the hull to crack. Five days later, the ship had sank, though the masts were still visible above the water.

In late 2022, plans were underway by the UK Government to remove the rusting masts for safety reasons in case their collapse should trigger the explosives below.