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

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

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

Step into a pastel time capsule where candy is truly dandy.

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

America's smallest national park site is the former residence of exiled Polish national hero Thaddeus Kosciuszko.

Yo, Adrian!

Ant sculptures march up the side of what used to be an iconic spot in punk rock lore.

World's first "penitentiary," meant to be humane, drove men insane.

Alexander Hamilton’s creation caused quite a bit of controversy.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

Instruments, apparatus, and rare books all relating to chemistry and its related sciences.

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

A clone-tree in Washington Square Park sprung from seeds that went to the Moon and back.

A layered tribute to the work of mosaicist Isaiah Zagar.

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

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

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

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

This beloved marketplace mascot poops money and grants good luck.

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.

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

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.