The Amazon was a region in South America on Earth.
In 1827, the Eleventh Doctor, Amy Pond and Rory Williams visited the Amazon. (AUDIO: The Eye of the Jungle)
On 1 May 1873, Professor Cornelius Perkins and his expedition discovered what they called "a frog the size of a rhinoceros" with the leg of one of the natives in its mouth as they were searching for the city of the Maygor tribe: the legendary Lost City of Gold. (AUDIO: The Valley of Death)
In the 1920s, George Cranleigh went on an expedition to the Amazon in search of the black orchid. (TV: Black Orchid)
In the 1970s, the newly-married Clifford Jones and Jo Grant went to the Amazon in search of a rare fungus. (TV: The Green Death) While in the Amazon, Jo sent back the Metebelis crystal given to her by the Third Doctor. (TV: Planet of the Spiders) At one point, after months of travelling in the Amazon, Jo tried to call the Doctor but he had left UNIT. (TV: Death of the Doctor)
Circa 2001, Charles Moore Wedderburn went on an expedition to the Amazon and discovered the Metahedron there. (PROSE: Falls the Shadow)
Circa 2060, the Amazon's ecosystem collapsed and the rainforest turned into a desert. (AUDIO: Loups-Garoux)
In the 51st century, the Amazon was a desert. The Eighth Doctor and Izzy Sinclair went there after detecting a distress call, which they traced to the Keep. (COMIC: The Keep)