The Battle of the RÝver Plate (December 13, 1939) was the first major naval battle of World War II, which resulted in the eventual sinking of the German pocket battleship - heavy cruiser Admiral Graf Spee by scuttling, ending her successful three-month campaign against British merchant shipping.
The British force, comprising the heavy cruiser HMS Exeter (six 8" guns) and light cruisers HMS Ajax and HMNZS Achilles (both eight 6" guns), engaged the German cruiser close to the estuary of the Rio de la Plata, or Silver River, between Argentina and Uruguay. Following intense gunnery action where the German cruiser had the advantage of longer range and heavier guns, while the British were able to divide fire, the Graf Spee eventually headed for Montevideo harbour in Uruguay.
Exeter had been severely damaged in the battle, and British propaganda efforts were made to convince Captain Hans Langsdorff of the Graf Spee that an overwhelming British force was being assembled, when in fact only the heavy cruiser HMS Cumberland was available and was being sent from the Falkland Islands.
Intense negotiations were undertaken, Uruguay being neutral. While the ship was prevented from leaving the harbour, Captain Langsdorff consulted with his command in Germany. He received orders that permitted various options, but not internment in Uruguay. He chose to scuttle his ship in the Rio de la Plata estuary (December 17) to avoid risk to the crew, a decision that is said to have infuriated Hitler. The crew of the Graf Spee was taken to Buenos Aires, where Captain Langsdorff subsequently committed suicide.
The prisoners taken by the Graf Spee prior to her sinking of enemy ships were transferred to her German supply ship Altmark, from which they were freed (February 16, 1940) by a boarding party from the British destroyer HMS Cossack while in J°ssingfjord, in neutral Norwegian waters.