Seneca Caverns-Registered Natural Landmark is "The Caviest Cave!" Walk natural stone steps and pathways through the "Earth Crack" and view Ole Mist'ry River. Shop Hollowrock Gifts for minerals, nature books, apparel, and other gifts. Pan for gemstones at Seneca Mining Company. Open Memorial Day-Labor Day, daily 9 am-6 pm; May and Sept-mid-Oct, Sat-Sun 10 am-4 pm or by appointment. Last tour departs one hour before closing.