The first green space constructed on an elevated viaduct.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

The artist and his brother are buried in a landscape straight out of a van Gogh painting.

One of the most powerful religious centers in the Middle Ages, dubbed the founder of Western monasticism.

Five miles of underground river link lake to ocean.

The first park built over a freeway is a brutalist masterwork.

An obscure waterfall that looks like something out of a fantasy novel.

This former coal gasification plant found a curious second life as a popular public park.

A French chateau, failed utopian community, odd museum, and Stonehenge replica in rural Washington State.

A wall of chewing gum moonlights as collective art.

A museum dedicated to the history and exploration of both popular music and science fiction.

A 100-year-old purveyor of curiosities, curios, and kitsch featuring mummies, shrunken heads, and a Fiji Mermaid.

A giant Troll lurks under one of Seattle's oldest bridges.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

This ancient theater was once the home of fierce gladiatorial battles.

The world's largest reflecting pool is just two centimeters deep.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

Lyon's miniature version of the Eiffel Tower was built as a statement in support of French secularism.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

The celebrated eyesore created by starry-eyed sweethearts.

This emotive sculpture was originally created for the 1878 World's Fair.

The video game-themed street art first popped up in the French city.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."