Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

One of only two commuter aerial tramways in the United States.

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

A crumbling hospital from the 1850s on Roosevelt Island.

The highest point in the state of New Hampshire, and while unlikely "the worst weather in the world," it sure seems that way to hikers.

An ancient glacial pothole waterfall in the heart of the Green Mountains.

The quaint little Vermont town played a quaint little Connecticut town in Tim Burton's "Beetlejuice."

Collapsing castle on the Hudson river was once the storage site of military surplus business.

Infamous marsh filled with toxic waste, World War II-era London rubble, and dead mobsters galore.

The home of one of America's most wealthy industrialists is now a historic site that remembers a more decadent time in the country's history.

Mysterious 500-year-old tapestries depict a unicorn hunt.

A historic Black graveyard hidden in the parking lot of one of America's largest malls.

The first neighborhood to implement the Garden City model in its suburban planning.

Frank Lloyd Wright’s most iconic home dangles over a Pennsylvania waterfall.

An abandoned saucer-shaped monument in the Bulgarian mountains.