This 19th century machine put animals (including humans) in boxes to study how they metabolized calories.

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

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

The first of Lancaster's "rural cemeteries."

Nothing says indulgence like a 1,500-pound chocolate castle.

A giant ball made from pieces of an old Jeep.

The final resting place of two members of the infamous Doan gang, notorious outlaws and Revolutionary War Loyalists.

Pittsburgh's literal underground railroad.

A museum dedicated to the history & joys of the trail & your best chance to see hikers throwing up ice cream.

A rock maze opens up to a panoramic viewpoint at an abandoned mine full of ghost stories.