Ruins of an early Roman Christian church dating back to the 4th to 5th centuries.

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

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

"Unity, Creativity, Beauty."

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

A striking symbol of the Bulgarian capital.

A flamboyant five-story building in Bulgaria resembles a crawling snail.

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

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

An abandoned saucer-shaped monument in the Bulgarian mountains.

Trimmed trees grow alongside the graves like topiary tombstones.

An ancient knight and a symbol of the city's freedom.

A self-proclaimed libertarian micro-state on a tiny bit of disputed territory between Serbia and Croatia.

A tribute to an iconic act of defiance from the Croatian War of Independence involving a small car.

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

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.

Gargoyle head that brings good luck.

Monasteries on rock pillars, once accessible only by frayed ropes.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

Abstract monuments express sorrow and resilience at the site of a horrific massacre in Nazi-occupied Serbia.

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

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Swarovski's museum/theme park is a fake diamond fantasia overlooked by a giant.

The first mosque in the world to receive electricity.