A field of nothing but boulders which resembles a giant's gravel driveway.

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

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

This meticulously extracted nervous system allegedly came from a 19th-century custodian who donated her body to science.

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

A toxic ghost town sitting atop a massive coal fire.

A model of a dinosaur that was named for Andrew Carnegie stands outside the museum that also bears his name.

The residents of the Neighborhood of Make-Believe live without much fanfare within the Pittsburgh Children's Museum.

This spectacular public market has got meat, fish, vegetables, baked goods, and enough kielbasa for a lifetime.

One of Philadelphia's largest murals resides hidden under this bridge.

These lush botanical gardens employ the most purrfect pest control force.

The fastest transatlantic ocean liner sat abandoned in a Philadelphia shipyard for decades.

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

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

This hidden gem of a garden has one of the only surviving Victorian ferneries in America.

There aren't too many operational funiculars around, but Pittsburgh has two!

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

The oldest surviving botanic garden in the United States.

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.

This might just be the TARDIS of bookstores.

Frank Lloyd Wright’s most iconic home dangles over a Pennsylvania waterfall.

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.

The taxidermied remains of a once-great parrot.