| Operation Highjump | | 20th | 26 August 1946 | February 1947 | Operation Highjump, officially named the United States Navy Antarctic Developments Program, was a massive US Navy operation to set up the Antarctic research base called Little America. The United States sought to train naval personnel there, test equipment in icy conditions, develop techniques for establishing and maintaining air bases, increase knowledge of the area’s hydrographic, geographic, meteorological, geological, and electromagnetic conditions, and developing techniques for establishing and maintaining air bases on ice. In doing so, the ambition was also to establish US sovereignty in Antarctica. | Antarctica |
| Antarctic Treaty | | 20th | 1 December 1959 | | The Antarctic Treaty is an agreement between 12 countries, namely Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, Russia, the United Kingdom, and the United States. The objective of the treaty is to recognise that it is in the interest of all humanity that Antarctica continues to be used exclusively for peaceful purposes and that it does not become the scene or object of international discord. It also recognises the freedom of scientific research and cooperation for that purpose, prohibiting the establishment of military bases and the testing of weapons of war. | Antarctica |
| German Antarctic Expedition | Schwabenland Expedition | 20th | 17 December 1938 | 11 April 1939 | The German Antarctic Expedition, also known as the Schwabenland-Expedition, was a Nazi-German expedition seeking to claim an area now known as Dronning Maud Land, which had previously been explored by Norway, who claimed it after learning about the German expedition. Germany’s goal was to create blubber production from raw materials such as whale oil, thereby avoiding relying on Norwegian blubber imports. The surveyed land was claimed by Germany in August 1939 as ‘Neuschwabenland’, named after MS Schwabenland. The German claim was subsequently abandoned in 1945. | Antarctica |
| Hope Bay Incident | | 20th | 1 February 1952 | | The Hope Bay Incident was an armed conflict between the United Kingdom and Argentina that took place in Antarctica. Argentina accused the British of wanting to build a new base in Antarctica when they started to unload material without consulting them. The British maintained that they already had a base there and that they wanted to rebuild it as it had been destroyed by fire. The incident ended with the withdrawal of the British, who later returned and built their base in a new position away from Argentina. | Antarctica |
| Deception Island Incident | Raid on Deception Island | 19th | 15 February 1853 | | The Deception Island Incident, also known as the Raid on Deception Island, was a conflict between the United Kingdom and Argentina that took place on 15 February 1953. Argentina built a facility where two Argentine soldiers lived, claiming to be in Argentine territory. The United Kingdom accused Argentina of invading their territory and arrested the two soldiers for not having a permit. It ended with the British destroying the Argentine safe haven. The two governments subsequently agreed not to interfere in each other’s bases. | Antarctica |
| Operation Tabarin | | 20th | 26 April 1905 | 1946 | Operation Tabarin was a secret United Kingdom expedition to Antarctica during World War II. The principal objective was to reinforce British claims to sovereignty of the Falkland Island Dependencies, establishing bases and carrying out administrative activities. Part of the mission was to prevent the Nazi-German government from setting up bases in Antarctica. Since the outbreak of the war, Argentina and Chile had also made claims to the Dependencies. | Antarctica |