This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

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

The video game-themed street art first popped up in the French city.

A surrealist timepiece by the artist of melting clocks.

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

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

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

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

Overlooked by many, the two famous Scottish warriors guard the main gate of Edinburgh Castle.

Overlooking the burial ground is a tower designed to prevent thieves from snatching the recently deceased.

Near the former site of numerous witch burnings, this lavish Edinburgh mainstay pays homage to Scotland's brutal history.

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

Now home to a drinking establishment, this building has a macabre history.

Edinburgh's oldest statue hides within a parking lot behind the city's iconic cathedral.

A sweet symbol marks the place where torturous executions were once carried out.

The 20th-century chapel’s intricate woodwork includes amazing details, most notably angels playing bagpipes.

Sprawled across the Great Hall ceiling are various constellations and images relating to the zodiac.

This otherwise ordinary close on the Royal Mile constituted the end of the world for Edinburgh’s poorest residents.

This obscure walkway links Edinburgh’s Old Town with one of the city's prime vantage points.

A roadway designed for a visiting monarch.

This mundane post marks the old location of the city's main postal hub.

Since 1973, this block has been home to the most concentrated collection of murals in San Francisco.