|Launched||14 January 1936|
|Commissioned||1 February 1937|
Unterseeboot 20, or more commonly U-20 was a German Type IIB U-boat of the Kriegsmarine. She was commissioned on February 1, 1936. During the German War, she conducted operations against enemy ships. She famously sunk HMS Birmingham of the coast of the Netherlands, the first loss of life in the war.