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

Eastern Bloc nostalgia, anybody?

This once-grandiose behemoth of a monument from the socialist era now sits quiet and closed up.

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

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

An abandoned saucer-shaped monument in the Bulgarian mountains.

Rotterdammers' dirty minds gave this Santa a dirty nickname and cursed it to a life of wandering.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

This basement museum explores the art and artistry of fascism.

Amsterdam's former hotspot for public executions and dissections.

A public urinal so pretty, it was declared a national monument.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

This unattributed sculpture in Amsterdam is hiding in plain sight.

This bird-loving brewery is situated in an old municipal bathhouse, nestled beside a 300-year-old windmill.

A beautifully eclectic mix of architectural styles.

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.

The history and future of cannabis.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

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

Cat art as far as the eye can see.

Established in 1638 to battle the Black Death, this botanical garden is a treasure trove of rare flora.

A floating cat sanctuary on an Amsterdam canal.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.