This historic furnace was once used to produce cannonballs during the Civil War.

No one knows who painted this mysterious mural in a Penn State basement.

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

One Pittsburgh musician's decades-in-the-making memorabilia collection is on display at this rock-n-roll curio shop.

The oldest surviving presidential residence in the United States.

Each step is a mere four inches tall, said to be measured by the stride of a woman wearing a hobble skirt.

A curious building honoring past and current members of a historic musical comedy troupe.

Where the oil industry began.

A preserved 18th century homestead in Western Pennsylvania marks the spot where the Whiskey Rebellion began.

Featuring the largest CinemaScope screen in Pennsylvania, this drive-in has entertained moviegoers for more than half a century.

A retired firefighter created this contraption so he and his family wouldn't die if accidentally buried alive.

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

An Irish Memorial commemorating those who perished due to potato blight.

A hidden piece of Altoona's railroad history in a long-forgotten abandoned town.

The mortal remains of a Russian prince, priest and paranormal investigator who came to America in 1792.

Current docking place of the SS United States, the fastest transatlantic ocean liner.

A museum dedicated to the strange and extravagant costumes and memorabilia of the mummers, a tradition older than Philadelphia itself.

This Old Testament garden features 100 plants from biblical times.

A modern ghost town whose inhabitants were driven away by the growth of nuclear power.

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

This permanent exhibition celebrates the finest of our heartless automatons both real and fictional.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

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

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