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.

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

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

A historic covered bridge is but one example of an oddly prevalent American urban legend.

Yo, Adrian!

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

This hidden gem of a garden has one of the only surviving Victorian ferneries in America.

A clone-tree in Washington Square Park sprung from seeds that went to the Moon and back.

Dr Barnes' $25 billion private collection of art and arboretum.

This Philly cemetery is the eternal home of many famous area residents, including Rocky Balboa's wife.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

Huge masonic hall in Philadelphia with lavishly themed rooms.

In which a local geological marvel becomes a quaint roadside attraction.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

This little-known collection holds everything from "Dracula" notes, to the manuscript of "Ulysses," to the forged works of Shakespeare.

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

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

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

A rare view of a preserved Victorian science museum.

Mysterious rocks that ring musically when struck.

World's first "penitentiary," meant to be humane, drove men insane.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

Beautiful Gothic-inspired lighthouse stands out among the run-of-the-mill striped fare on Bodies Island.