A neo-Gothic castle in the Argentinian countryside.

A memorial to the victims of Argentina's "Dirty War."

A gateway to a mysterious network of underground tunnels.

A tower devoted to — and modeled after — the Divine Comedy.

This giant power line tower is a robot that can express its moods in neon.

Xul Solar was an artist of alternate worlds, inventor of languages, and dreamer of utopias.

This historic, palatial theater is now one of the world’s most beautiful bookstores.

105-foot wide giant metallic flower blooms anew every day in the heart of Buenos Aires.

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

A grassy pyramid named after a French battle.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

Invisible bridge parts the waters, invoking biblical images and preserving the ominous feel of an ancient moat.

A Belgian self-built tower inspired by the Bible and ancient civilizations.

Hiding the longest subterranean river known in the world.

Sculpture designed by Turkish artist and professor Mehmet Ali Uysal.

A 14th-century fortified keep showcases the masterpieces of an ingenious 20th-century clockmaker.

A little sculpture with a large wardrobe.

The Devil’s own choice when he needs a drink in Brussels.

Ancient man-made caves underneath small town Belgium.

Petting this mysterious iron monkey supposedly brings good luck.

One of the deepest indoor swimming pools in the world.