Two geoglyphs that are truly unique to North America.

The hallowed remains of a 900-year old Ancestral Pueblo great house.

A former nuclear facility during the Cold War turned nature preserve.

In the middle of a New England forest sit the crumbling ruins of World War II-era ammunition storage bunkers.

Prolific outsider artist Sid Boyum's concrete sculptures add whimsy to Madison's Schenk-Atwood neighborhood.

La Cara del Indio honors the Taíno chief who fought bravely against the Spanish invasion of Puerto Rico.

Every summer, the Mendenhall River greenbelt comes alive with an explosion of magenta flowers.

These fossilized remains of an ancient saber-toothed cat inspired the mascot of Nashville's NHL team.

This remote Colorado canyon is home to the second-largest collection of natural arches in the world.

The short hike is worth the stunning views and crystal blue waters of a secluded beach.

Drift through underground caves on a tube.

Located in the world's highest-altitude Dark Sky Community, this observatory welcomes amateur and professional astronomers alike.

Ute tour guides have been sharing the ancient dwellings and rock art inside this large park with visitors for more than 40 years.

Home to fossils and other specimens from the Western Interior Seaway.

These falls, sometimes called the "Niagara of the West," still put on a good show at the right time of year.

Journey inside the bowels of this sperm whale sculpture.

A tribute to two brothers' artistic endeavors.

In the power of this waterfall, Alexander Hamilton saw the potential for industry.

A small cave hidden deep within the Jenny Jump State Forest.

The flow from this waterfall sometimes comes out of springs below its rim.

What started as three small gnomes at the base of a tree has grown into a full-blown gnome home.

Take an underground boat ride through a former hydraulic raceway that was built in the late 19th century.

On the edge of grassland in northeastern Colorado, these rock formations are some of the few remnants of a high plain that has eroded away over millions of years.

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.