Five ancient libraries, little changed for centuries, preserve a medieval archive of Quranic lore and civic documents

An architectural relic that survived the hands of time.

This remarkably well-preserved mosque stands amid an 11th-century caravansary.

The world's newest astronomical clock is also its most accurate.

The 700-year-old fortress was the site of Count Orlok's castle in "Nosferatu."

Romania's only crater lake with water as pure as if distilled.

Gigantic Romanian salt mines used to heal respiratory conditions.

This fortress-like monastery is covered with intricate frescoes.

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

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

This sign marks the entrance to a tiny proto-state within the small country of Moldova.

The Grand Mall in Varna hosts one of the biggest collections of Soviet-era paraphernalia in Bulgaria.

Mysterious standing stone formations looks like a petrified forest.

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

Rebuilt several decades ago, its striking murals prevent it from being reconsecrated as a church.

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

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

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

The second-largest Jewish temple in Bulgaria was deserted after World War II, seized by the communist government and then abandoned again.

Climbing to the top of the cathedral's bell tower offers sweeping views of these medieval ruins.

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

The legendary cliffside castle of three-time Voivode of Wallachia, Vlad the Impaler.

Even drowned in an ocean of toxic waste, the remnants of this Romanian village stand tall.

A medieval church built up to defend its village.