South Philadelphia is home to Keith Haring's only surviving in situ collaborative public mural.

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.

The house where the writer spent his formative years.

The oldest active church in Pennsylvania is also the second oldest Swedish Church in the United States.

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

This beloved marketplace mascot poops money and grants good luck.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

The modern birthplace of Irish freedom.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

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

A local prank turned town icon.

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

One of Ireland's most infamous prisons for rebels including men, women and children.

This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

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

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

This Philly cemetery is the eternal home of many famous area residents, including Rocky Balboa's wife.

One of the oldest of its kind.

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

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

One artist's love letter to his city and its citizens plays out across dozens of bright murals painted on the sides of decrepit buildings.

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

The taxidermied remains of Charles Dickens' pet raven, which helped inspire one of Edgar Allan Poe's most famous poems.