Enchanting gardens surround a derelict mansion, all hidden in plain sight behind a stone wall.

This weeping, 10-foot-tall sculpture was a maquette for a 9/11 memorial.

This collection of odd proofs of concept is like taking a walk through the imagination of a Victorian engineer.

Time travel with sweets across history at this research-based candy store.

The meeting of the northwestern corner of Delaware, the northeastern corner of Maryland, and the southern edge of Pennsylvania.

Although built to generate electricity for Marylanders, this dam has become an all-you-can-eat buffet for American bald eagles.

A Civil War Museum with some notable medical antiques.

This shale formation along the Appalachian Trail once inspired the third president of the United States.

Built in the 1850s, this church was of the first five churches constructed in Harper's Ferry.

This advertisement for talcum powder was painted on the rock face and has since defied removal.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

One of the only memorials dedicated to journalists who died in combat.

Memorializing an American tragedy of massive proportions.

This museum is dedicated to the first coast-to-coast highway.

A bronze statue of Mister Rogers in the neighborhood where he grew up.

A larger-than-life statue of America's favorite sundae marks the place it was invented.

The universally beloved children's television figure is interred on a high hilltop in one of western Pennsylvania's oldest cemeteries.

These disused steel furnaces are now haunting ruins that may one day be a national park.

The Paul Bunyan of the steel industry.

This eccentric mansion museum holds a impressive collection of rare and automatic instruments.

A quiet, gothic haven nestled between Pittsburgh's Squirrel Hill and Point Breeze neighborhoods.

The United States’s oldest funicular railway glides up and down a steep Pittsburgh street.

This spot memorializes one of the greatest plays in NFL history, unless you happen to be a Raiders fan.

A piece of baseball history is preserved in a Pittsburgh parking lot.