Grand Orthodox cathedral with walls filled with frescoes and icons.

Step inside this medieval Orthodox gem and travel back to the 16th century.

This fifth-century church is one of the oldest Christian sites in the Balkans.

This building has two facades of clashing architectural designs.

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

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

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

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

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

A striking symbol of the Bulgarian capital.

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

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

Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

Double spiral staircases are not unheard of, but they are very rare.

A little sculpture with a large wardrobe.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

Climb inside an iron crystal magnified 165 billion times its normal size.

This unusual hostel provides a glimpse of life in a city under siege.

A monument on the pavement marks the spot where two cultures that shaped Sarajevo come together.

A small museum built by a family that survived the Siege of Sarajevo.

This unique museum focuses on the Siege of Sarajevo through children's eyes.

The sad remains of a monument to martial arts legend and movie star Bruce Lee—in the middle of Balkans.