People have been living in the cave houses on this Italian hillside since the Neolithic era.

A 16th-century horror show built in a lovely Italian garden.

A controversial artwork draws attention to the dark history of Prague's "Suicide Bridge."

Bohemian paradise covered in majestic forests.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

A sulfuric hellscape in southern Italy.

Pilgrimage site for star-crossed lovers.

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

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

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

Eastern Bloc nostalgia, anybody?

Ruins of a 10th century church tucked away deep in a botanical garden.

Roman-era ships unearthed...

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.

The ancient Greek Titan guards this massive dam holding a lightning bolt to symbolize electricity.

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

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

An abandoned saucer-shaped monument in the Bulgarian mountains.

An homage to the medieval rulers of Bulgaria.

This massive concrete sculpture is said to be the heaviest communist monument on Earth.

Mysterious standing stone formations looks like a petrified forest.

The site of many battles and tragedies, including the 40 maidens who leapt into the sea.

Massive, unfinished broadcasting station stands as a monument to the fall of communism.