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

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

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

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

A small flooded ghost town with a few scattered structures remaining.

An Ancestral Puebloan ruin that appears to burst into flames in the sunlight.

A desert settlement founded and later abandoned by Hawaiian members of the Church of Jesus Christ of Latter-day Saints in Utah's Skull Valley.

This ghost town was once a cult-like religious utopian settlement.

This quiet park's strange sedimentary spires were named after Kodak's color film.

Settled by the Church of Jesus Christ of Latter-day Saints in 1859, this abandoned frontier town has appeared in several films.

One man has installed bathtubs into the Utah desert floor to harness the powers of a natural hot spring.

An earthwork sculpture built by Robert Smithson in the Great Salt Lake only reemerges during drought.

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.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

This geothermal hot spring hides beneath a slowly growing mineral dome.

The site of the "Bone Wars" between two rival paleontologists during the dinosaur rush of the 19th century.

A river runs through this remote valley in a very unexpected way.

Unlike most arches, this geological oddity formed in a volcanic dike.

There are eight natural springs around town, each with a slightly different taste.

At one time this small mining village was the highest town in America but now it sits abandoned while the mine churns on.

Possibly the world's only drive-in movie theater with an attached motel.

Colorado's only true geyser is hidden within the San Juan National Forest.

This deserted Gold Rush town is home to a Masonic lodge that, strangely enough, still holds meetings.