Divers have tried to find the end of the lake, but their attempts failed. America's "Lost Sea" can be found deep beneath an unassuming corner of Tennessee: the largest non-subglacial underground lake in the US, and perhaps the second largest in the world. This massive body of underground water is found in the Craighead Caverns and is so vast that no one knows how big it … [Read more...] about America’s Subterranean “Lost Sea” Is So Vast It’s Never Been Fully Explored