Deep under the Earth's surface, discovering beauty and science
Cave explorer and geologist Francesco Sauro travels to the hidden continent under our feet, surveying deep, dark places inside the earth that humans have never been able to reach before. In the spectacular tepuis of South America, he finds new minerals and insects that have evolved in isolation, and he uses his knowledge of these alien worlds to train astronauts.
Gallery: A journey into the world's most puzzling caves
Francesco Sauro shares astonishing images from a trip into what might just be the oldest caves in the world.