A unique collection of diving equipment spanning antiquity to the present day.

This ancient cave is home to a museum, bar, and is filled with fluorescent minerals.

The fifth-longest natural arch in the world, and the longest outside China.

Hundreds of drawings left by the land's previous inhabitants remain mysterious.

A tunnel with windows, so you don't miss out on the impressive views.

A house carved into a rock in the 1940s.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

Two geologically young and nearly circular volcanic subsidence craters, each about a half-mile in diameter, abruptly break the nearly featureless Snake River Plain.

This Idaho state park boasts the tallest single-structured sand dune in North America.

A legal loophole makes it possible to get away with murder within this 50-square-mile section of Yellowstone.

The world's first nuclear power plant is open to visitors looking to role-play a meltdown.

One of the "twins" in these falls on the Snake River was sacrificed for hydropower generation in the 1930s.

The only bridge in the United States where BASE jumping is legal without a permit year-round.

Where the famed daredevil attempted to launch himself across a canyon in a custom-built rocket.

A cable-suspension footbridge that hangs high above the Mill River.

The world’s largest underground marble quarry is hiding in Vermont.

The highest peak in the state of Vermont has some interesting features.

Scary metal statues adorn some of the signature buildings of Burlington, Vermont.

This 38-drawer structure claims the superlative title, but it isn't the world's only giant filing cabinet.

Tour the world's largest deep-hole dimension granite quarry, where you can view the plant where gravestones are made and roll a ball down the outdoor granite bowling alley.

The sweetest graveyard in the world is filled with headstones for dearly de-pinted ice cream flavors.

This cavernous abandoned marble mine is popular with ice skaters in the winter.

Colorful sand dunes create a unique attraction in this part of Utah's red-rock country.