1513 Turkish world map, full of European state secrets and snarky commentary.

A marvel of Byzantine engineering under the streets of Istanbul.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

A curious collection dedicated to human and animal anatomy and pathology.

The last Oostende trawler to fish off Iceland is now a museum.

The former home of a trailblazing surrealist is still filled with haunting dolls and grim paintings.

You would never come across this tiny green oasis if you didn't know it existed.

This rose and lavender oil distillery still operates as it did more than a century ago.

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.

Rock carving created 1,300 years ago 75 feet off the ground.

This massive stone and steel monument remembers a century-old battle that cost thousands of lives and nearly destroyed the city.

Eastern Bloc nostalgia, anybody?

A mountain pass in Bulgaria's Balkan Mountains was the site of four historic battles.

A magnificent, glittering building tucked into a tiny Bulgarian mountain town.

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

A collection of art from Bulgaria's time as a communist state.

A spectacular Bulgarian cave resembling a devil's head with a waterfall rushing down its throat.

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

UNESCO-protected ancient burial ground.

A striking symbol of the Bulgarian capital.