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

An abandoned coal mine reached by a steep hike.

Hikers can still stroll beneath the long conveyer of this abandoned mining facility hidden in a West Virginia river gorge.

The remains of one of the last mining camps developed on the New River.

An abandoned 1920s school with a mysterious history.

America's first serial killer rests in anonymity.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

Enchanting gardens surround a derelict mansion, all hidden in plain sight behind a stone wall.

A scenic fort on the harbor protected Philadelphia from an attack that never came.

WWII-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers. .

A wrecked ship dating back to the American Revolution was only recently discovered off the Delaware coast.

Come for the Italian food, stay for the taxidermy and giant statues.

World War II bunker still standing on the New Jersey beach.

The rusting remains are visible sticking out of the waters of the Delaware Bay.

The remains of an old sawmill, gristmill and the surrounding industry dating back to the 18th century.

This historic iron-working village is now a ghost town so immaculate that it looks as though it was recently built.

The first partially complete dinosaur skeleton was discovered here, forever changing the world's view of the ruling reptiles.

Instruments, apparatus, and rare books all relating to chemistry and its related sciences.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

A clone-tree in Washington Square Park sprung from seeds that went to the Moon and back.

For more than 25 years, this Philadelphia store has been offering a wide selection of Victorian oddities and antiques.

An ancient Viking village in North America that predates Columbus by 500 years.

This candy-striped tower is the farthest east you can go in the United States.