Mount Roraima is a tepui — a table-top mountain with sheer cliffs and a flat summit, rising high above the surrounding forest and grassland. It sits where the borders of Venezuela, Brazil and Guyana meet.

The sandstone it's made of is extremely ancient, among the oldest rock formations on Earth. The summit is often wrapped in cloud and drenched by rain. Waterfalls pour off its edges. On top, a strange landscape of black rock, crystal and pools is home to plants and animals that live nowhere else.

Accounts of the tepuis by explorers are often said to have inspired Arthur Conan Doyle's 1912 novel The Lost World, in which dinosaurs survive on a remote South American plateau.