Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

After the queen of Spain had a dream where these statues fell and crushed her, they were removed from the palace and given new homes around Madrid.

The oldest operating roller coaster of its kind, the Montaña Suiza has been thrilling riders since 1928.

Dive into an undersea optical illusion off the coast of Mauritius.

A museum dedicated to the history of sugar cultivation on Réunion island.

On one of the world's most active volcanoes, a pebble-filled crater changes color with the wind.

A futuristic rocket marks the spot where three borders meet.

A town that sets itself apart with supersized designer seating.

A plain wooden seat that once belonged to one of the most prominent figures of the Protestant Reformation.

The world's largest second-hand graces a clock surrounded by constantly changing flower beds. 

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

The highest pedestrian bridge in Singapore looks like a series of undulating waves rising between two public parks.

Singapore's landscaping project is home to 18 incredible Supertrees.

At the foot of an active volcano sits a church miraculously spared by its lava.

This Bordeaux parking garage has 712 indoor spaces, and one outdoor.

Historic medieval fortified city in southwest France.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Two towns are linked by an engineering marvel masquerading as a boring suspension bridge.

Giant topiary dog once played a role in a terrorist bomb plot.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

The only museum with its curator—and her pets—buried inside.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Two stone columns flank the grand Venice square, but there were supposed to be three.