Argentine Antarctica mainland. Argentina was the only nation to have an Antarctic base for 40 years until the British built a base on the same islands. Argentina bases its claims on this sector of Antarctica on the following grounds: Argentina's claim to the Antarctic Peninsula overlaps with the Antarctic claims of Chile, 53°W to 90°W, and the UK claims, 20°W to 80°W. Currently, there are no attempts by Argentina or any other country to enforce territorial claims in Antarctica. See List of Antarctic territorial claims. None of these claims have international recognition and have been suspended by the Antarctic Treaty in 1961.
Brazilian Antarctica May 1975, making the first official mention of the Frontage Theory, which states (simplified) that sovereignty over each point in Antarctica properly belongs to the first country whose non-Antarctic territory one would reach when travelling north in a straight line from such a point. The Frontage Theory ("Teoria da Defrontação") was proposed by Brazilian geopolitical scholar Therezinha de Castro and published in her book "Antártica: Teoria da Defrontação". Outside the zone of interest, Brazil maintains a permanent staffed research facility, the Comandante Ferraz Brazilian Antarctic Base (UN/LOCODE: AQ-CFZ), located in Admiralty Bay, King George Island, near the tip of the