Magnetic mine

A magnetic mine was a type of naval mine developed by Nazi Germany. In the first months of World War II, they wreaked havoc on the Royal Navy.

On 22 November 1939, a Luftwaffe bomber dropped a magnetic mine over the Thames Estuary. The Admiralty recovered the mine on 23 November and began studying it, allowing them to devise countermeasures to protect British ships from its magnetism. (AUDIO: The Oncoming Storm)