South America was an Earth continent.
History
The Second Doctor, John and Gillian visited South America and helped a native village defend themselves from an enemy tribe. (COMIC: The TARDIS Worshippers)
Vampire bats wwere only found in South America, (TV: The Chase) as was the black orchid flower. (TV: Black Orchid)
In 1911, the Forge harvested vampire DNA in South America. The DNA was used in Project: Twilight. (PROSE: Project: Valhalla)
In the late 20th century, amidst growing tensions between Russia and China, fighting broke out in South America and southern Asia before Sir Reginald Styles was able to negotiate peace, cooling the crisis and preventing World War Three, with the Third Doctor preventing an alternate timeline where Styles was assassinated and war did indeed come to pass. (TV: Day of the Daleks)
In 1977, Brigadier Lethbridge-Stewart investigated an Inca pyramid in South America. (AUDIO: The Cloisters of Terror)
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)
During the 2010s invasion of Earth by parallel universe Cybermen, South America was among the places where they landed. (AUDIO: Master of Worlds)
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)
One South American jungle was home to a mushroom known as the Great Power. The Daleks travelled to this jungle to obtain it, where they were defeated by the First Doctor and the Chief Voord. (PROSE: Doctor Who and the Daleks)
Mondas
On Mondas, the twin planet of Earth, the landmasses resembled those of Earth but were mirrored and upside down. Ben Jackson pointed out Mondas' equivalent of South America. (TV: The Tenth Planet)