Bristol Caverns is an exceptional underground attraction featuring an underground river — believed to be one the Cherokee used as a mountain highway for centuries — flowing through dramatic stalactites, stalagmites, and flowstone formations. Guided tours of approximately 45 minutes lead visitors through a half mile of illuminated passages at a constant 58-degree temperature. The cavern system is among the most visited natural attractions in the Tri-Cities region. A perfect activity for hot summer days or rainy weather.