One man's stunning attempt at eco-friendly living.

This small chapel built into rock is the oldest place of worship in Luxembourg.

This magenta statue commemorates the legendary marriage between a mermaid and the city's founder.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

Statues of a fire-breather, a clown, and a whole performing troupe celebrate Luxembourg's creative side.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A mosaic-tiled house built by graveyard sweeper Raymond Isidore.

The famous winding walk at Chartres is surrounded in mystery and myth.

A sublime medieval path adorns the marble floor of one of the most beautiful Gothic cathedrals in France.

Eat a Nobel banquet from any year in the basement of Stockholm's City Hall.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

Sweden's "good old days" painstakingly re-created in a model village.

Outside a Viking museum sits a modern-day runestone made by a Swedish runemaster using traditional methods.

This statue and park honor the Swedish chemist Jacob Berzelius, one of the founders of modern chemistry.

Now a hotel, this former bank was the site of a robbery that spawned a psychological phenomenon.

A temporary art piece to celebrate LGBTQ Pride is now a permanent part of Stockholm's traffic landscape.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

It houses the remains of a 17th-century version of the Titanic.

A heated statue pays tribute to one of Sweden's great actresses.

A golden plaque marks the site of the mysterious unsolved assassination of the former Swedish prime minister.

Stockholm's tiniest statue is of a small boy looking at the Moon.

Stockholm's narrowest alley is barely over two feet wide.

The Swedish flag over this small naval fort signals that the nation is at peace.

Stockholm's deepest subway station is also a stunning ecological wonder.