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

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

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

What looks like a simple quaint estate in rural Pennsylvania was in the 18th century home to a small monastic community.

An Irish Memorial commemorating those who perished due to potato blight.

This dramatic rail curve was once the target of a failed Nazi attack.

These lush botanical gardens employ the most purrfect pest control force.

A tradition unlike any other, this marks the site of the annual Groundhog's Day tradition.

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

Behold the rickety wooden glory of the world's oldest operating roller coaster.

Current docking place of the SS United States, the fastest transatlantic ocean liner.

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

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

The Pennsylvania landscape depicted by a quarter mile of mosaics made from used road signs.

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

The oldest farmer's market in America is so ancient it was approved by the King of England.

A failed piece of Orientalism has become the proud symbol of a community.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.

The internal railway of one of the biggest steel plants in America has been transformed into a linear park with unique industrial views.

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.

This might just be the TARDIS of bookstores.

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

One artist's love letter to his city and its citizens plays out across dozens of bright murals painted on the sides of decrepit buildings.

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