Dry lakes, also known as playas, are flat, dry areas that were once filled with water but have since evaporated. They are typically found in arid or semi-arid regions and can vary in size. When water evaporates, it leaves behind minerals and salts, creating a unique landscape that can be stark and beautiful. These lakes can serve as important ecological zones, providing habitats for various wildlife during rare wet periods. Additionally, dry lakes are often studied for their geological features and can be significant for understanding past climate conditions. Examples include the Great Salt Lake in Utah and the Salton Sea in California.