On rare days, this abandoned castle's gatekeepers open its doors, revealing the eye-popping splendor hidden inside.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

This ancient village and its adjoining cemetery have a beautiful history of death and remembrance.

An ethereal glowing blue ocean cave in Croatia.

Yugoslavia's biggest underground airport lies in ruins.

Space-age monument to an early 20th-century uprising.

Eastern Bloc nostalgia, anybody?

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

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

An abandoned brutalist monument whose history has been lost to the ages.

Croatia's towering concrete blossom grows from the site of a World War II concentration camp.

On top of a resort town as old as the Bronze Age sits an incredible war memorial statue overlooking the beaches below.

This 3,800-year-old site contains markers used to study the movement of the sun and moon and create a lunar calendar.

This brutalist monument is inscribed with 9921 names of Yugoslav partisans who perished during WWII.

One of the world's oldest olive trees, thought to be over 2,000 years old.

This exclusive resort has completely covered a tiny Balkan island in a 5-star warren of guest rooms.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

A full figure 4th century incorruptible saint lies in a glass coffin in Croatia.

Former military fort and site of untold horrors during WWII, this island may become the Adriatic's next luxury resort.

A beautiful mountaintop mausoleum devoted to a Montenegrin icon can't seem to make everyone happy.

A curious little museum dedicated to the furry feline in the cat haven that is Old Town Kotor.

The remains of the last Bosnian fortress to fall to the Ottomans are still standing.

Bridge that died in war and was resurected.