Instruments, apparatus, and rare books all relating to chemistry and its related sciences.

This Pennsylvania cave holds evidence of the oldest known inhabitants of North America.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.

South Philadelphia is home to Keith Haring's only surviving in situ collaborative public mural.

One of the oldest of its kind.

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

A diorama of the Civil War, fought by cats.

The first of Lancaster's "rural cemeteries."

A museum and research center dedicated to preserving the history of Rolls-Royce and Bentley motorcars.

A take-out restaurant that only serves cuisine from countries with which the United States is in conflict.

America's smallest national park site is the former residence of exiled Polish national hero Thaddeus Kosciuszko.

Mysterious rocks that ring musically when struck.

The legacy of baseball great Roberto Clemente is preserved in a retired Pittsburgh fire station.

The site of the little-known Pennsylvania battle that sparked the Seven Years' War.

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

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

An intriguing three-sided folly is a testament to one man's devotion to Catholicism and the number three.

Each spring this woodland floor is carpeted with purplish flowers as far as the eye can see.

Built by the patron saint of illusionists this Elizabethan manor house is riddled with secret cubbies for hiding priests.

The world's oldest family-run magic shop is hidden beneath a bustling London thoroughfare.

The curious and tiny collection contains some very odd objects.

"We gonna rock down to Electric Avenue, and then we'll take it higher..."

The last occupied troglodyte dwellings in England weren't abandoned until the 1960s.

This luxury shopping lane has been protected by its own tiny police force for over a century.