Legend says this mysterious stone head belongs to a woman who was petrified by an alchemist.

Drink wine handed out through a window as part of an age-old tradition.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

Banksy gives themself artistic license with this piece of London street art.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A kaleidoscopic warehouse-maze of handmade neon signs.

One of Europe's largest supercomputers is housed inside of a disused chapel.

Turntable anonymously received orphans, alms, and groceries.

A stately palace has been converted into the world's largest cannabis museum.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Week-long block party becomes a competition for the best decorated street.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

This cemetery features modernist statues as strange as its name.

This semi-secret storybook hedge maze is also the oldest garden in the city.

The house that took a plunge into the facade of a museum.

A patriotic medieval knight in driven-nail armor raised money for widows and orphans of WWI.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.