Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

The only museum dedicated to the history of the "Magic Lantern," a medieval slide projector.

Home of the International Space Hall of Fame.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Natural catch-basin rocks covered in thousands of drawings spanning many millennia.