Antarctica’s oldest continuously occupied basecamp is the Laurie Island weather station, which was claimed by Argentina in 1904. That being said, the British made the first formal claim on Antarctic territory in 1908—ultimately handing over the Ross Dependencies to New Zealand in 1923. Territorial claims picked up with France laying claim to Terre Adlie in 1934, Australia claiming an extensive portion of territory in 1933, Norway claiming Dronning Maud Land in 1939, and Chile claiming sovereignty of the Antarctic Peninsula (along with Argentina and Britain) in 1940. In 1938, German planes dropped hundreds of swastika-inscribed aluminum darts over Dronning Maud Land in the hopes of claiming vast territories for the Third Reich. Meanwhile, the U.S. held no claims over Antarctica, though the government did establish the U.S. Antarctic Service in 1939.
WWII interrupted government research pursuits in Antarctica, but Antarctica didn’t disappear off the world stage. The Germans used the Peninsula and the sub-Antarctic islands as a home base to attack allied shipping vessels, and the British established secret bases at Hope Bay and on Wiencke and Deception Islands.