The world's largest salt flat, Salar de Uyuni is located at an elevation of 12,000 feet (3,656 meters) in Bolivia’s Altiplano and is so flat that its height varies by only about a yard over its 4,000 square mile extent. It is also a valuable source of lithium, and perfectly illustrates the conflicting objectives of maintaining beautiful natural environments and the development of technologies that will help us wean ourselves from carbon. The stunning reflections result from a thin layer of water that collects from time to time in various areas of the salt flat.