The loneliest island in New York.

These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.

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

This innocuous New Mexico storefront was once the secret jump-off spot for Manhattan Project scientists.

This Canadian island is a veritable garden of decay with countless abandoned structures dotting the landscape.

The longest navigable underground river in the United States is home to countless blind and albino animals.

These disused steel furnaces are now haunting ruins that may one day be a national park.

Hidden in plain sight on the Hudson River is an abandoned train station where nature has taken over.

Another of California's unused Cold War missile defense complexes has become a graffiti gallery.

What was once the largest mine in North America has left behind a hollow hill filled with bright blue waters.

On Japan's Tashirojima Island, cats are king.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

World's only nuclear reactor operated by liberal arts undergraduates.