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

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

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

The origin of this mechanical boy was a mystery until he revealed his maker by writing it in perfect cursive.

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

Golden and naked, the figure that was once the highest point in New York is all that remains of the second Madison Square Garden.

Yo, Adrian!

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

Enjoy a slice while browsing the world's largest collection of pizza memorabilia.

This Philly landmark has a giant butterfly pavilion, three floors of insect displays, and withstood a $40,000 heist.

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

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

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

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

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

Designed by Horace Trumbauer in 1893, this Gothic-style castle is now a home for academics.

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