A well-preserved example of an early industrial operation in the northeastern United States.

The longest covered bridge in Delaware.

Descendants of this colonial Pennsylvania family still travel from far and wide to visit the 300-year-old home of their Quaker ancestors.

A beloved horticultural oasis on the grounds of a wealthy family's former estate.

A converted hangar displays dozens of helicopters, from a famous 1943 rescue chopper to several autogyros.

The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.

A blend of art, antiquities, and Americana fill this museum, surrounded by whimsical, enchanting gardens.

World War II-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers.

What began as an art installation is now the private drinkhaüs for a brewery's employees.

Come for the Italian food, stay for the taxidermy and giant statues.

The rusting remains are visible sticking out of the waters of the Delaware Bay.

World War II bunker still standing on the New Jersey beach.

Step inside Lucy, the world's largest "elephant."

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

A daily replay of the experiment that proved the rotation of the Earth.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

The fastest transatlantic ocean liner sat abandoned in a Philadelphia shipyard for decades.

This elaborate towering structure was once famed for its revolutionary height.

Board a mine car and descend the #190 slope 300 feet underground into the Clark Vein of coal.

The abandoned coal loading dock is a canvas for unsanctioned art.

This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

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

Yo, Adrian!

The first American department store, and home to the largest operating musical instrument in the world.