A soon-to-be-forgotten roadside spectacle loaded with local lore.

An industrial waste tourist attraction.

A smaller model of the Da Vinci sculpture that took 500 years to come to life.

A former plant in one of the hubs of U.S. steelmaking has been turned into this museum celebrating the history of American industry.

An abandoned railroad tunnel transformed into a creepy path for hikers and cyclists.

Designed by Horace Trumbauer in 1893, this Gothic-style castle is now a home for academics.

One of the first commercially successful anthracite-powered iron-making operations in North America.

Where the oil industry began.

A pride of the state, this working museum crafts pottery mosaics in the style of Pennsylvania's earliest European settlers.

For decades, it has disappeared and reappeared as water levels rise and fall.

Pennsylvania's highest point is spotted with boulders which were pushed to the surface by nothing but cold.

This icon of the Atomic Age now lays dormant.

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

One of the U.S. Forest Service's only mansions is outfitted with a dinner table for floating food.

Contrary to what one might expect, ice forms inside this small cavern during the summer and melts during the winter.

Once on display alongside a giant Gumby, it’s as tall as a nine-story building when fully extended.

The home and studio of a visionary woodworker now stands as a museum and example of his artistic genius.

A local prank turned town icon.

This Pennsylvania cave holds evidence of the oldest known inhabitants of North America.

These disused steel furnaces are now haunting ruins that may one day be a national park.

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

This titanic java kettle is one of the many kitschy landmarks located along America's OTHER famous highway.

This lush forest valley was once mined for lumber to the extent that it was once nicknamed "The Pennsylvania Desert."

The internal railway of one of the biggest steel plants in America has been transformed into a linear park with unique industrial views.