This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

New York's oldest magic store.

This hospital fell into ruins after failing to act as the advocate for the mentally ill it was designed to be.

These mystical miniature houses bring a touch of magic to the New Jersey woods.

Series of storm drains connected to a dark urban legend.

A recently abandoned psych ward at the end of Sanatorium Road.

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

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.

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

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

The first railway tunnel to cross the Continental Divide and, at 11,523 feet, was once the highest railroad tunnel in the world.

A dangerous narrow-gauge railroad once traced a route through this striking canyon.

Take a self-guided tour through one of Colorado's most elevated mining districts.

Two tall rocks sit at the center of this site, once the home of a large Ancestral Puebloan community.

It takes a nine-mile hike to reach these hot springs, but weary hikers are rewarded with stunning views and a warm soak.

A glimpse of a waterfall is reached by a steel catwalk along a slot canyon located in an Ouray city park.

Only a few signs remain of the buried Colorado mining town that supplied the uranium for the first atomic bomb.

Isak Heartstone, a 15-foot wooden troll made out of recycled materials.

This National Natural Landmark is one of the best examples of a “mass wasting” in the world.

The decaying ruins of a failed mining company’s water diversion project cling to the side of a desert canyon.

This now-abandoned outcrop is an important Native American spiritual site, overtaken by European settlers and mining pollution.

Once a lonely sentinel on the edge of the Great Plains, this rebuilt trading fort offers a glimpse of life on the Santa Fe Trail.

An enthusiastically interactive mining museum that won't let black lung ruin the fun.