Where Is the World's Largest Underground Lake?

Dragon's Breath Cave, located in the Otjozondjupa Region of Namibia, contains the world's largest known underground non-subglacial lake. The lake sits about 66 meters below the cave entrance and covers approximately 2.61 hectares (about 5 football fields). Its depth has been measured to at least 212 meters, though divers believe it could be deeper. The cave gets its dramatic name from the humid air that rises from the warm water below, creating a misty "breath" at the entrance. The lake's water is crystal clear but contains almost no aquatic life apart from a unique species of golden catfish found nowhere else on Earth.