This might just be the TARDIS of bookstores.

Mysterious rocks that ring musically when struck.

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

One of the oldest of its kind.

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

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

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

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

Yo, Adrian!

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

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

A pride of the state, this working museum crafts pottery mosaics in the style of Pennsylvania's earliest European settlers.

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

These 20-foot sculptures will help guide you from the local train station to the local sculpture garden.

A unique sculpture park that specializes in the huge and bizarre.

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

This strange, big-tailed beast became a Pennsylvania town's unofficial mascot.

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

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

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.