A six-story treehouse offers spectacular views of New York's Finger Lakes region.

The lost town of Neversink, sunk by New York City.

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

A graveyard of bathyspheres and diving bells paints a weirdly accurate account of ocean exploration's rickety history.

Bad farming practices caused this unnatural natural wonder.

In Rickwood Caverns, visitors can travel hundreds of feet underground and see beautiful formations unique to the region.

Once one of the largest producers of pig iron in the world.

Buildings that dynamite couldn't bring down were abandoned because of bathroom issues.

This monument is dedicated to those lost on June 6, 1944, in the town with that day’s highest per-capita casualty rate.

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

This natural wonderland is a unique chance to explore a Carolina bay, a mysterious geological formation of unknown origin.

The only Florida state park with publicly accessible caves.

The longest covered bridge in Delaware.

West Point’s only monument to a woman veteran stands above an empty grave.

The poet's been ambling through these New York woods since 1940.

It wouldn't be long after purchasing this farm, Brown would lead his siege on Harper's Ferry.

This historic mini-suspension bridge was swept away once but is now here to stay.

True to its name, this bouncy walkway may be the world’s smallest suspension bridge.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

An outlandish shoe shaped house built by an eccentric millionaire.

Memorializing an American tragedy of massive proportions.

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

This picturesque stream was up until recently the site of a ten story mountain of slag and sewage.

A mysteriously abandoned campsite in San Angelo State Park.