A Roman monument to their own civil engineering prowess.

A giant portrait of an ancient king looms over the river.

This 14th century castle withstood years of battle but is now sliding off the hills into the Danube.

Stone age urban planning.

Religious perseverance and cultural coexistence manifest in an architectural gem that multiple wars couldn't topple.

This dazzling Art Nouveau mansion is now home to the Modern Art Gallery Subotica.

A well preserved medieval fortress in Vojvodina.

A beautiful 19th-century mansion slowly crumbled and became a 'ghost house' after World War II.

Backwards hour and minute hands and a timing mechanism that fluctuates with the temperature led to this clock tower's local nickname.

A maze of underground tunnels beneath one of the most beautiful forts in Serbia.

A misnamed well, with a deep dark past.

These stairs feature the names of Zemun's most famous faces.

A small memorial to a deadly night in Serbia that shook the world before it was swept under the rug.

A museum dedicated to the former country.

Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

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

A medieval church built up to defend its village.

This Transylvanian church has changed its denomination four times.

Some call this eerie forest of crooked trees the "Bermuda Triangle of Romania."

The Natural History Museum that time forgot.

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

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

Eastern Bloc nostalgia, anybody?