An underground river cave discovered in the 1880s and open for public tours since the 1940s, Bristol Caverns features a naturally flowing subterranean stream, impressive stalactite and stalagmite formations, and a comfortable constant 58-degree temperature year-round. Guided tours of 45 minutes navigate the lit pathways above the underground river. The cave is one of Sullivan County's top tourist attractions and a refreshing cool-temperature escape during summer months.