German submarine U-121 was a long-lived Type IIB U-boat

U-boat

U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

 built during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 for service in the Kriegsmarine

Kriegsmarine

The Kriegsmarine was the name of the German Navy during the Nazi regime . It superseded the Kaiserliche Marine of World War I and the post-war Reichsmarine. The Kriegsmarine was one of three official branches of the Wehrmacht, the unified armed forces of Nazi Germany.The Kriegsmarine grew rapidly...

. The U-121 spent the entire war as a training vessel and was scuttled at the end of the conflict.

The U-121 was one of two Type II U-boats built at Flender Werke

Flender Werke

Flender Werke was a German shipbuilding company, located in Lübeck. It was founded in 1917 and was at a time one of the largest shipyards in Germany.During World War II, Flender Werke built 2 Type II and 40 Type VII U-boats for the Kriegsmarine....

 in Lübeck

Lübeck

The Hanseatic City of Lübeck is the second-largest city in Schleswig-Holstein, in northern Germany, and one of the major ports of Germany. It was for several centuries the "capital" of the Hanseatic League and, because of its Brick Gothic architectural heritage, is listed by UNESCO as a World...

. Like her sister ship (also built in Lübeck), she was originally built for export. The advent of World War II and increased training needs led the German high command to assign U-120 and U-121 to the training command instead.