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

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

This museum inside a museum tells the story of London's timepieces.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

This staircase in a lush tropical grotto was built by enslaved laborers and renamed to honor Queen Victoria's role in ending slavery in the British Empire.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

The library houses an incredible collection of some of the world's most impressive books and manuscripts.

The lighthouse central to the 1980s horror classic "The Fog" is, in fact, located in one of the foggiest areas of the Pacific Coast.

The southernmost outpost of the Russian Empire in colonial America.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

These mysterious Viking chess pieces spent centuries hidden on a remote Scottish island.

Built to repay the sins of the father, this church is home to one of the most valuable works of Western art.

A series of three shiny letters mark the boundary of an old refuge for those being pursued by debt collectors.

The walls and streets of the ancient city are peppered with penises.

Quito's historic, main square dates back to the 16th century.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

Skulls and skeletons are omnipresent in this church dedicated to souls trapped in purgatory.

Watch the newest land on the planet form before your eyes.

A galaxy of glowworms—larvae of a gnat—hides deep in the belly of these caves.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

Legend has it this fountain built to symbolize the Pope’s power hides a strange secret concerning Neptune's manliness.

The space-age building is home to one of the few remaining rotating restaurants in America, and the only one that inspired a 1980s sitcom.