Limestone caves with spectacular showcase chambers.

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

An out of this world experience.

Founded by members of the Tohono O’odham Nation, this one-room joint's James Beard–winning fry bread is light as a cloud.

America's only nuclear missile silo open to the public.

Cleveland's giant "free" stamp is a nod to the Civil War, but was misinterpreted for years.

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

More than 350 million years ago, western New York was covered in a vast sea. Today, you can dig up the remains of the plants and animals that lived there.

The only boathouse Frank Lloyd Wright ever designed was also the only unbuilt structure in his famous Wasmuth Portfolio, until 2007.

The absurd creation is a compulsory destination for selfies in Buffalo.

This unique crypt designed by Frank Lloyd Wright for his longtime friend was not completed in either man's lifetime.

One of Frank Lloyd Wright's greatest—and favorite—architectural masterpieces was almost lost.

World's largest Christmas store.

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

The park is home to the United States's only still-operating Dutch windmill.

The spaceship-like theater, which is still in use, was one of the most popular exhibits at the 1964 New York World's Fair.

This cave holds a surprisingly colorful variety of geological oddities.

A bizarre house filled with an astounding array of collections.

The only diamond mine in the world where you can keep what you find.

A 56-foot tall statue of the god of fire looks out over Birmingham, Alabama.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

Winding country roads in eastern West Virginia lead to an extraordinary place populated by fiberglass giants.

Extraordinary objects lurk in this quintessential regional museum.