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

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

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

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

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

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

Yo, Adrian!

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

The oldest surviving botanic garden in the United States.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

The Tudor-style cottage in the middle of the square is not quite what it seems.

Originally built for London’s cab drivers, this bright green hut now serves anyone a hot drink or meal.

A cluttered and astounding collection of antiquities and curiosities.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

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

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

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

This quarter-mile tunnel under the Bluff in Pittsburgh bends at a 45-degree angle.

The largest clock face in the United States is twice the size of Big Ben and infinitely more ad-sponsored.

A model of a dinosaur that was named for Andrew Carnegie stands outside the museum that also bears his name.

This Old Testament garden features 100 plants from biblical times.

A restored Pittsburgh house of God has been converted to a marvelous house of suds.