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

The only geyser in the state of Pennsylvania is caused by pressure from an abandoned coal mine outside of the ghost town Centralia.

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

This decommissioned surface-to-surface missile resides outside the American Legion Post in Pennslyvania.

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

Once in a state of dilapidation, this candy-inspired fortress is now being revived.

Tucked behind New Jersey's abandoned Gingerbread Castle lie the eerie ruins of a once-flourishing paper mill.

It would take 35 firetrucks to fill this enormous glacial pothole.

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

Oldest existing wire suspension bridge in the United States.

The graffitied ruins stand hidden within the Pennsylvania woods.

Mysterious rocks that ring musically when struck.

This eerily well-preserved coal town was saved from destruction by a Sean Connery movie.

A park full of outsider art, created by college students studying outsider art.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.

Once the world's largest reinforced concrete structure, this abandoned bridge now beckons urban explorers.

This huge, disused viaduct is now a crumbling concrete underworld of covered in years of graffiti.

These beautiful ruins deep in the Pennsylvania woods are thought to have been a ski lodge or a speakeasy, but no one really knows.

An ideal wedding spot that is almost too ideal.