The Lost World is a novel by Arthur Conan Doyle concerning an expedition to a plateau in South America where prehistoric animals (dinosaurs and other extinct creatures) still survive. The character of Professor Challenger was introduced in this book.
The novel has been adapted to film many times, the first time in 1925. This version was directed by Marion C. Cooper and featured pioneering stop motion special effects by Willis O'Brien; this version has been deemed "culturally significant" by the Library of Congress and selected for preservation in the United States National Film Registry.
The Lost World is also a 1995 novel by Michael Crichton. It is a sequel to his earlier novel Jurassic Park.
Like Conan Doyle's novel, it concerns an expedition to an isolated South American location where dinosaurs roam - though in this case, the dinosaurs were recreated by genetic engineering, rather than surviving from antiquity.