Erected in 1697 this Philadelphia bridge is the oldest surviving roadway bridge and perhaps the oldest stone bridge in the United States.

Yo, Adrian!

The world’s first penitentiary, meant to be humane, drove men insane.

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

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

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

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

Huge masonic hall in Philadelphia with lavishly themed rooms.

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

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

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

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

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

The oldest surviving botanic garden in the United States.

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 extraordinary Depression-era expenditure was modeled after a postcard of a Mediterranean hotel.

In the bowels of a 19th-century brewery lurks a fine-dining restaurant offering an array of themed feasts.

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

The home and studio of a visionary woodworker now stands as a museum and example of his artistic genius.

An eccentric priest's tribute to George Washington, this chapel tells the story of the American Revolution.

This historic old movie house was the scene of one of the Blob's most iconic attacks.

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