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

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

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

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

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

"Dark Sky Park" is heaven on Earth for astronomers, one of the rare U.S. locations with no artificial light pollution.

A stone arch leads to a cavernous 1930s spring house tucked away in the Pennsylvania woods.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

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

World's first "penitentiary," meant to be humane, drove men insane.

Mysterious rocks that ring musically when struck.