Cannon of the German warship Graf von Spee, sunk in 1939 by its crew in front of Montevideo, in the first months of the World War II.
After sinking several British merchant ships in the South Atlantic, the Graf von Spee was attacked by three vessels of the Royal Navy (Exeter, Achilles and Ajax). After the fight the German ship took refuge in the port of Montevideo to repairs. Finally, the captain Langsdorff ordered its destruction.
The canon on the photo was recovered in 1997 and is on display at the entrance of the Naval Museum of Montevideo.