A daily replay of the experiment that proved the rotation of the Earth.

Frank Lloyd Wright built this suburban synagogue late in life, but it stands among his most iconic masterpieces.

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

An indoor miniature village and labor of love for Laurence Geiringer, a model railroad enthusiast.

Beautiful views of the surrounding hills and birds of prey can be found at this sanctuary.

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

Inside this 150-year-old barn turned antique shop is a vast array of items for curios hunters.

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

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

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

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

Yo, Adrian!

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.