A tepui is a flat-topped mountain or mesa found primarily in the Guiana Highlands of South America, particularly in countries like Venezuela, Guyana, and Brazil. These geological formations are characterized by their steep cliffs and unique ecosystems, often hosting a variety of endemic plant and animal species due to their isolation. Tepuis are often referred to as "islands in the sky" because their summits are typically covered in dense vegetation and can be home to unique habitats. The most famous tepui is Mount Roraima, which has inspired various myths and legends, including those in the works of author Arthur Conan Doyle.