These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

A gigantic statue of a Russian soldier watches over the ancient city of Plovdiv, a prominent reminder of the Soviet period in Bulgaria.

An abandoned saucer-shaped monument in the Bulgarian mountains.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

This bone-filled cave got its name after they found 140 bear skeletons inside.

Celebrated example of Ottoman architecture that also served as a site for brutal massacres.

A solar-powered primary school inspires hope and experimentation in a country ripe for energy innovation.

Even drowned in an ocean of toxic waste, the remnants of this Romanian village stand tall.

A sinuous path among steep cliffs creates a stunning sight in southwestern Serbia.

A stunning 18th century pharmacy and medieval chemist's collection.

The legendary cliffside castle of three-time Voivode of Wallachia, Vlad the Impaler.

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

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

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.

Eastern Bloc nostalgia, anybody?

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

Operating continuously since 1903, this "milestone" facility transformed the regional economy.

Religious structure known for its sculpted details.

The growing stones of Romania.

The second-largest Jewish temple in Bulgaria was deserted after World War II, seized by the communist government and then abandoned again.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

A Red Cross memorial museum at the site of the Niš concentration camp that operated for four eventful years during World War II.

A futuristic, brutalist masterpiece that is also strangely prison-like.