In use from 1742 to 1910, only flat headstones were allowed in this cemetery.

One of the world's oldest continually operating bookstores.

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

Visitors to Salt Springs State Park are encouraged to literally put their two cents in Penny Rock.

This extraordinary Depression-era expenditure was modeled after a postcard of a Mediterranean hotel.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

A daily replay of the experiment that proved the rotation of the Earth.

A 90-foot-tall psychedelic "tree" on the side of the highway has baffled passersby for decades.

This concert pavilion on the shore of the Great Salt Lake has been destroyed by fire, water, and disinterest but keeps coming back.

Miraculous tree that seems to sprout out of solid rock.

Ever wanted the laymen's version of your credit card fine print?

Infamous marsh filled with toxic waste, World War II-era London rubble, and dead mobsters galore.

Hidden in plain sight on the Hudson River is an abandoned train station where nature has taken over.

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

Yo, Adrian!

The first American department store, and home to the largest operating musical instrument in the world.

The oldest farmer's market in America is so ancient it was approved by the King of England.

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

A toxic ghost town sitting atop a massive coal fire.

In the power of this waterfall, Alexander Hamilton saw the potential for industry.

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

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

An exotic wildlife habitat right off The Strip.

Elvis's own personal tropical hideaway.