A scenic fort on the harbor protected Philadelphia from an attack that never came.

Hidden deep within New Jersey Pine Barrens is a massive graffiti wonderland.

An allegedly cursed tree represents a town's reckoning with a racist past.

The tombstone of the founder of the lost town of Ogletown is now stuck inside a traffic median.

One of the world's largest model railroads is a mind-boggling achievement.

Mysterious rocks that ring musically when struck.

One of the oldest surviving Swedish-American homes in the United States.

A drab two-story office space in Delaware is a hidden tax haven for Hillary Clinton, Donald Trump, and over half the Fortune 500 companies.

This local gem houses the largest collection of pre-Raphaelite paintings outside of the U.K.

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.

The highest point in Delaware is located under a trailer so this marker across the street will have to do.

This giant disembodied horse head seems to balance impossibly on its nose.

Surrounded by industrial sprawl, a small monument marks the site of William Penn's first landing in Pennsylvania.

Designed by Horace Trumbauer in 1893, this Gothic-style castle is now a home for academics.

North America's oldest quarantine facility was built in response to Philadelphia's 1793 yellow fever outbreak.

This museum boasts a bucket of teeth and tells the tale of a 20th-century dental circus.

The first American axe throwing club.

The world's third-largest crystal sphere has sat in the Penn Museum since 1927 with the exception of one outlandish theft.

The origin of this mechanical boy was a mystery until he revealed his maker by writing it in perfect cursive.

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

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

Century-old shop, specializing in Occult products.