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

Strange red rock formations that have been attributed to a higher power for hundreds of years.

See massive fossils that are over 200 million years old in northeastern Arizona.

Natural sonic phenomenon comes with a grisly legend of murder and blood.

A multi-storied adobe complex has been inhabited for more than a thousand years.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

Large one-man sculpture park in Michigan.

The world's second largest single-dish radio telescope, once used to contact E.T.

One of the largest crucifixes in the world stands 55 feet tall in a secluded, wooded area of northern Michigan.

A museum dedicated to the alleged Roswell Incident.

A sprawling collection of over 106,000 toys from around the world.

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

A museum celebrating the self-taught artist-environment builder.

As its grandiose name implies, this wooden dome is unsurpassed in size.

This historical theme park celebrates all things noodle.

This massive wooden building contains a giant Buddha, healing pillars, and tame deer wandering the grounds.

The stoutest tree in the world.