The South Pole was the southernmost point on Earth, located in the continent Antarctica.
In December 1986, (TV: The Tenth Planet) the First Doctor came across the Twelfth Doctor at the South Pole, as both battled with the idea of refusing to regenerate. When time suddenly froze, Captain Lethbridge-Stewart came through from Ypres, 1914, and the three boarded the Twelfth Doctor's TARDIS. (TV: Twice Upon a Time)
In 1983, the Eleventh Doctor's TARDIS' HADS activated when a Soviet submarine at the North Pole was attacked by Skaldak. The TARDIS left the submarine and surfaced at the South Pole. (TV: Cold War)