Snail Shell Cave in Rockvale near Murfreesboro, Tennessee, is a limestone cave within an 88-acre preserve owned by the Southeastern Cave Conservancy. With more than 9 miles of surveyed passages, it is the longest continuous cave in the Tennessee Central Basin and part of a larger system exceeding 13 miles. Entered through a dramatic sinkhole with steep walls, the cave contains a stream that can be followed in either direction. Though the opening was long known locally, deep water delayed serious exploration until September 1951, when Tom Barr and Bert Denton made the first modern entry. The cave is also a highly significant protected biological site, and dangerous flooding restricts access to skilled, authorized cavers.