19th century cemetery hidden in Brooklyn's Prospect Park.

An abandoned subway tunnel that could have reinvigorated Staten Island still lies somewhere beneath this Brooklyn park.

Empty, but not abandoned, this cavernous Brooklyn loading dock was once considered the largest individual building in the world.

This seemingly unremarkable boulder is said to bear the hoofprint of the devil himself.

I fought the law and the precinct caved in.

A way to take your secrets to someone else's grave.

This small, hidden cove is home to abandoned boats.

One Brooklyn man's collection of life-size fiberglass statues has taken over his entire yard.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A crumbling hospital from the 1850s on Roosevelt Island.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

The longest non-mortared wall in the country is one man's tribute to his displaced Yuchi ancestor's five-year journey to her homeland.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

Bubbling up from deep underground is the warm crystal clear water that fills the Warm Springs Pools, America's oldest spa.

A cult archaeology conspiracy theory claims these West Virginia petroglyphs were written by Irish monks in Ogham.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

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

This fairy tale-themed amusement park is now abandoned, and childhood metaphors abound.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.

This disastrous New Jersey safari park saw animal attacks, escapes, and disease before being abandoned.

An eerie, decaying ghost town destined to fade into the forest.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.