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

A cave's rare beauty held a cavernous secret hidden underground.

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

This is one really big nut.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

A museum dedicated to the alleged Roswell Incident.

America's post-nuclear-attack chambers of Congress.

Home of a 28-foot tall stalagmite known as the War Club.

Jacksonville's highways rendered this century-old grammar school unusable.

This natural spring is the winter home to the largest gathering of manatees in the world.

A replica of one of the more than 15,000 civilian lookout towers that lined the U.S. coast during World War II.

A building so large that it has its own weather.

Look closely and you’ll notice that the color changes a third of the way up the tower.

More than 7,000 gallons of water pour over these cascading red quartzite waterfalls every second.

One devoted couple has donated multiple recreations of Michelangelo's sculptures to this South Dakota town.

Known as "The Hill of the Little Devils."

This hidden oasis features a stunning view of the Hudson River and the Palisades from a castle-like museum.

This historic hotel on Bathhouse Row in Hot Springs National Park has a storied history of gangsters and baseball greats.

This Arkansas town is known for its gangster history, its healing waters, and now its brews.

Two gushing waterfalls of hot spring water within a block of each other.

This evocative New Jersey statue memoralizes the Polish victims of a Soviet massacre.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

One of two giant blue cockerel statues erected with an intentional double meaning.

A toweringly silly piece of modern art has been delighting locals since the 1980s.