This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

For part of the year, this innovative greenhouse is painted white to keep the plants from getting scorched.

The largest whale museum in Europe allows visitors to walk among life-size giants.

Instead of solid circles, the stoplights in this northern Icelandic town have glowing red hearts.

The Hveragerði fissure runs through this unassuming shopping center.

The vast chamber inside this abandoned cooling tower looks like something out of a sci-fi dystopia.

A little sculpture with a large wardrobe.

Theme park featuring miniature replicas of European monuments.

Climb inside an iron crystal magnified 165 billion times its normal size.

Lavish royal estate punctuated with heated greenhouses.

This cheese shop also houses a museum devoted to Dutch dairy.

Walk through the history of a Dutch truck manufacturer, from 1928 to today.

A market built atop boats is one of the few floating holiday markets in Europe.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

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

Just outside of Nairobi lies a large estate surrounded by endangered Rothschild giraffes, who have been fed from the window by Mick Jagger and Walter Cronkite.

The world's largest church atop a political fault line.

The largest mosque in Germany.

A condensed piece of China floating in a Dutch harbor.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

A little slice of Japan and its aesthetics in London's Holland Park.