This dormant volcanic crater has been converted from a roiling pit of magma to a pleasant hiking spot.

This giant temperature attraction created some giant electric bills.

The legacy of an unsolved, gruesome murder rests beneath the spans of this historic bridge.

This grave in a ghost town cemetery marks the death of a witch on a day that never happened.

This colorful monument commemorates a little-known story from the life of Abraham Lincoln.

This unassuming layer of clay boasts an out-of-this-world origin story.

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

The symbol was surreptitiously built into the river bank by German prisoners of war.

A museum dedicated to the alleged Roswell Incident.

This is one really big nut.

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

The former home of the army detachment that captured Geronimo.

What is the Thing?

This bomb shelter-themed bar has barely changed since it opened.

This iconic 1958 tower welcomes air travelers to Tucson with neon-lit letters and architectural style.

This church on a Tohono O'Odham reservation has stood since 1797.

Finally the worlds of UFO enthusiasts and beef jerky lovers have come together in this roadside shop.

A former utopian healing center created by a huckster and built by derelicts.

High in the Sacramento Mountains, a facility dedicated to studying the sun.

The second-largest ceremonial mound in the United States is an artificial hill that is loosely shaped like a pentagon.

A brick-lined alley full of public artwork tucked away in downtown Gulfport.

A cheeky alleyway window hosts tiny rotating exhibits with outsized charm.

The intricate geometry inside this Baroque-style dome was designed to create "terror of the human soul."

A fake medieval village in the middle of Turin.