One of the oldest surviving lock houses on the Ohio River.

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

Pennsylvania’s creepiest roadside attraction is a haunting example of roadside kitsch.

Home to an eclectic collection of over 200 vintage motorcycles, Americana, and some of the most extraordinary antiques from all around the world.

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

Don't get it twisted: This is the oldest pretzel bakery in the United States.

When oil was discovered just outside of Pittsburgh, the city became home to this regional stock market.

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

Beautiful views of the surrounding hills and birds of prey can be found at this sanctuary.

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

Color-coded signs direct drivers on a network of routes designed to avoid Pittsburgh traffic.

The site of America's first commercial oil well essentially disappeared after the town went bust.

In this cemetery stands the country's first public crematorium.

In the parking lot of a fast food restaurant, a statue memorializing a prolific bull elephant.

This Art Deco service station has been providing tune-ups and turning heads for close to a century.

An American flag was erected for every day that passed during the Iranian Hostage Crisis.

A private residence adorned with a gorgeous mural dedicated to the buzzing insect.

Overshadowed by quilts, the artistry of these patterned textiles went underappreciated for too long.

One of the oldest Catholic churches in the U.S., situated just east of Gettysburg.

This massive sycamore tree has been labeled as one of the largest in the state.

The only statue of its kind to commemorate Washington's beginnings as an officer of the British Colonial Militia.

Frank Lloyd Wright built this suburban synagogue late in life, but it stands among his most iconic masterpieces.

Inside this 150-year-old barn turned antique shop is a vast array of items for curios hunters.

A museum commemorating the Donora Smog, which killed 20 people in October 1948 and sparked national outrage over air pollution.