OHIO CAVERNS 2210 EAST STATE ROUTE 245 Tours take guests through two different parts of the cavern. The Historic Tour begins at the site of discovery and includes the part that was originally explored from 1897 to 1925. The Natural Wonder Tour takes guests on a 1 mile walk through parts discovered after 1925. It includes the largest stalactite in Ohio, The Crystal King, along with many other marvelous formations and colors. The Winter Tour is the only tour offered from October 1st through April 30th. It is a hybrid tour, showing guests highlights from both the Natural Wonder and Historic tours.