Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

This subterranean necropolis holds three floors of antler-dug grave caves.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

The world's northernmost brewery uses water from a 2,000-year-old glacier to create its beer.

This floating sculpture of ice is a poignant reminder of nature's power.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

In the northernmost city in the world, it's illegal to be buried because it’s too cold for bodies to decompose.

Sofia's legislative center is continuously reinventing itself.

Said to be the only museum in the world dedicated to the most classic of all blooms, the rose.

A vast Communist-era exhibition space in the Bulgarian capital.

"Holy Wisdom" overlooks the city that became its namesake.

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

UNESCO-protected ancient burial ground.

A striking symbol of the Bulgarian capital.

This historic black and white monastery is one of Bulgaria's architectural jewels.

A museum filled with tiny, adorable versions of the mighty Royal Danish Navy.

Site of the first radio and telephone broadcasting companies in Copenhagen.

An exhibition of preserved locomotives housed in a 1950s depot shows the history of Denmark's railway.

An "evil painter" included pointed symbols in this artwork to poke fun at members of the Danish Parliament.

Considered one of the most haunted places in Europe, this 800-year-old castle was home to noble prisoners.

The largest of Denmark's seven mysterious round churches stands on an island in the Baltic Sea.

This huge industrial sculpture looks like a UFO and a factory had a baby.

Danish observation tower designed to look like a giant beer bottle.

The only surviving piece of Copenhagen's 16th-century defensive wall.