So far, we’ve talked about above ground parks and underwater parks, but what about underground parks? There are plenty of opportunities to go spelunking in cave reserves around the world. The U.S. has plenty of them.

 

Missouri, in particular, is also known as the “Cave State,” boasting over 6,600 caves within its boundaries! Cave tours and guided tours are great ways to explore these parks. Caves have been sources of inspiration not only for geologists and biologists, but for great writers like Mark Twain.

 

Tourists can view Mark Twain Cave in Hannibal, MO where the classic author got the idea for the famous cave scene in The Adventures of Tom Sawyer (1876).