South America
From Tardis Wiki, the free Doctor Who reference
South America was an Earth continent.
The Second Doctor, John and Gillian visited South America and helped a native village defend themselves from an enemy tribe. (COMIC: The TARDIS Worshippers)
The black orchid flower was only found in South America. (TV: Black Orchid)
Following the plague sent by the Daleks during their 22nd century invasion of Earth a majority of the population of South America died before a cure could be found. (TV: The Dalek Invasion of Earth)
In Pete's World in 2004, the South American state reported that 265,000 people had gone missing, implied to be Cybermen experiments. (WC: Tardisode 5)