An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

Statue of death tucked in the University of Medicine courtyard.

A surrealist timepiece by the artist of melting clocks.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

A mechanized clock where a man fights off a dragon, crab, and rooster.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

Bronze sculpture celebrating the relationship between Churchill and Roosevelt.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

Public access to clean drinking water was an instant hit among the masses.

The John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

On October 17, 1814, a 15-ft. wave of beer ran rampant through the streets of London.

London's smallest police station is barely the size of a phone booth.

Storybook cottage in Beverly Hills was once the site of 1920s silent film studio, affectionately known as "The Witch's House."

It should come as no surprise that the best view of the Hollywood sign is from Batman's lair.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

Iconic Los Angeles residence famous for its 19 statues of Michelangelo's David.

Most famous work of one of Frank Lloyd Wright's sons.

A bigger-than-life pun that has become a beacon of altruism.

Non-profit time travel mart sells goods you would need for a trip through the fourth dimension.

America's most famous piece of self-built architecture.