Mark Twain immortalized the maze of underground passages where he played as a boy when he wrote the episode in Tom Sawyer where Tom and Becky get lost in McDougal's Cave. Guided tours last about an hour and start with a short video explaining the geology (the cave is 100 million years old and has 6.5 miles of passages formed by dripping water) and history (it was discovered by hunters in 1819, Jesse James use it for a hideout, and guided tours started in 1886). Guides are good about pointing out the "treasure room" where Tom and Huck found a box of gold and the corner of the cave where Injun Joe died. The Mark Twain Cave Tour is over level ground, with no stairs. On Saturdays, young folks portraying Tom and Becky join your tour. The cave complex also includes a campground, a shop where kids can pan for minerals and gemstones, gift and candle shops, and Cave Hollow Center, a meeting and event site. Admission charged.