The site of the first medieval crusade that pitted Christians against Christians.

Historic medieval fortified city in southwest France.

Half a century after it was abandoned, this ghost town is coming back to life.

This army of concretions is an unexplained geological phenomenon unlike anything else in the world.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

A chapel on a volcanic core, marking the end of a successful journey.

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

The remains of this castle, known as the Witch’s Eye, watch over the Thur Valley.

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.