In this episode, I take you to Hamilton, Ohio, to see the hollow-earth-inspired gravestone of one of the theory's biggest evangelists, and then we go to Estero, Florida, to see the remnants of a hollow earth cult whose definition of hollow earth is mind-blowing. Photos of my visit to the hollow earth-inspired grave of John Symmes. Photos of my visit to the remains of the Koreshan hollow earth cult. Address for the grave of John Symmes in Symmes Park: Sycamore St. and South Third St., Hamilton, Ohio. Address for Koreshan State Park: 3800 Corkscrew Rd., Estero, Florida. Want to learn about the oddities I visit in real time? Follow me on Twitter, Facebook, or Patreon. I also write other books that you can buy. Spooky books.