This museum houses a large collection of old motorcycles.

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

A scenic UNESCO site that doubles as a habitat for various forms of wildlife.

The elliptical citadel resisted the advance of the mighty Ottomans several times, thanks to the military prowess of the "Dragon of Albania."

The ridged layers that make up this river canyon represent Earth's geological history.

Operating continuously since 1903, this "milestone" facility transformed the regional economy.

Popular river that runs through the remote Serbian municipality of Leskovac.

Structure built from the skulls of vanquished foes.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

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

A historical puzzle lies at the origins of this structure.

Artists made this mosque into a marvel of Ottoman baroque architecture.

This stone figurine was made more than 6,000 years ago and depicts a female deity of the Neolithic Vinča culture.

The ceiling of this cavern is dripping with multicolored marble stalactites.

According to a local legend, this old castle could only be built after a woman was immured in the walls.

After witnessing the rise and fall of three empires, this ancient city was finally destroyed by a series of earthquakes.

An abandoned Byzantine fortress and notorious prison.

A two thousand year old brothel uncovered in Northern Greece.

These warring psychedelic crags commemorate an unsuccessful military operation.

This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

This top-secret nuclear bunker hidden in a Bosnian mountain has been converted to a modern art exhibition space.

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

A tiny chapel and burial site lurk underground in Jajce.

This cluster of little wooden huts once ground local farmers’ wheat into flour during the days of the Austro-Hungarian Empire.