Missouri has more than 6,000 explored caves, with oldest AND the newest show caves found in Hannibal. And, according to vacationideas.com, they are among the best.

Discovered in the early 1800s, Mark Twain Cave has a rich history. One of its early explorers was young Sam Clemens himself, who wrote about his exploits in the Adventures of Tom Sawyer. But did you know the cave was once a sort of warehouse for the dead? Dr. Joseph Nash McDowell was a surgeon who experimented on corpses in the bowels of the cave. He even stored his daughter's lifeless body there. That's just one of the interesting facts you'll learn when you take the hour-long tour of this natural wonder.
Mark Twain Cave first opened to visitors in 1886 and become the state's first show cave. And just across the way, you can also tour Missouri's newest show cave. The Cameron Cave tour is a more rustic look inside a natural wonder. Where its sister cave has electricity, paths and handrails, Cameron Cave offers a tour by lantern. You get more of a feel of how the early explorers experienced it.
And here's a bonus when you visit Cameron Cave or the cave made famous worldwide by Mark Twain: now matter how hot it gets this summer, the cave is always 52 degrees year-round. Find out more at marktwaincave.com