These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

The remains of this early 20th century refinery loom on a mountainside like a graffiti-covered fortress.

This abandoned factory on the Hudson River once churned out a million bricks a week.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

This Florida arena, once host to "the fastest game in the world," has sat empty for 25 years.

The haunting remains of a failed housing development can still be found behind the big box stores that were to anchor them.

The ruins of a Florida miracle spring resort make it seem like a wonder that this was ever a health spa.

Walk the same tracks that once ferried Gilded Age aristocrats to their vacation destinations.

In the heart of Brigham Young's promised land sits a festering plot of industrial ruin that has been claimed by society's outcasts.

Crumbling ruins mark the site of a couple's grisly murder in the woods.

Tucked away on an empty wooded lot in suburban Oklahoma City lie the remnants of an abandoned circus camp.

An abandoned early-20th-century boomtown sits within the Calico Rock city limits.

This overgrown Illinois water park offers a whole new type of adventure.

Collection of trolley cars in the woods represent one man's attempt to preserve transportation history.

A former connection to City Island, it has been abandoned since the 1930s.

The only runway directly into the magic kingdom has been closed since 1972, but it still sings to you if you drive fast enough.

This airfield is home to a number of retired vintage planes in various states of disrepair.

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

This railroad tunnel was once the longest in Massachusetts.

This former theme park in New York's Adirondack Mountains fell into ruin before being resurrected as a state-run campground

A deteriorating 1990s Girl Scout camp in a beautiful lush park on Lake Ontario.

Hidden in one of New York's oldest subway stations is the final remnant of the site of the bizarre Shakespeare Riots.

A planned settlement in Pennsylvania once housed the aristocratic refugees of the French Revolution.

The ruins of this long-abandoned unsuccessful gold mine can still be found.