Located at a lofty altitude of about 12,000 feet above sea level, Salar de Uyuni is the world’s largest salt flat (or salt pan), spanning just over 4,000 square miles. It was formed when prehistoric lakes dried up over centuries, leaving behind a desert of bright white salt that can be seen from space. During the months from December to April, a thin layer of water covering the salt transforms the area into a giant mirror that reflects the beautiful Bolivian skies. If you’re driving across the surface at such times, it can appear as though you are navigating through a highway of clouds.