The Lost Sea is the largest underground lake in the United States. It lies deep within a cave system called Craighead Caverns, in the mountains of east Tennessee. The actual caverns have provided shelter and secrecy for a number of people: the Cherokee used to inhabit a cave called the Council Room, and left behind a wide range of artifacts; soldiers stored ammunition here in the Civil War; and during Prohibition one of the caverns was used as a speakeasy.Today the prime attraction is the magnificent underground lake, which visitors can explore on electric-power, glass-bottom boats. The exact size of the lake is unknown because the cavern connects to larger flooded caverns directly below.
Exploring these deep underwater caverns can be dangerous, and as a result divers have only been able to map 13 acres (5 hectares) of the lake. Another fascinating attraction is the rare crystalline formations called anthodites. Composed of a form of calcium carbonate called aragonite, these delicate, hair-like objects are also known as “cave flowers.” They are found in only a few of the world’s caves, and have earned this cave’s national landmark designation.