Mount Everest
From Tardis Wiki, the free Doctor Who reference
Mount Everest was a mountain.
Everest stood at around 8km tall. (TV: The Waters of Mars)
In 1953, the first humans successfully climbed Mount Everest. (TV: The Idiot's Lantern)
Santiago Jones visited it during one of his journeys. (TV: Death of the Doctor)
At some point during the 51st century, the Doctor helped carry the Mona Lisa up Mount Everest on a camel to preserve it from a war. (PROSE: The Art of Destruction)
