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

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

Yugoslavia's biggest underground airport lies in ruins.

A crumbling World War I fort that is reached through a series of concrete tunnels.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

An abandoned 19th-century iron factory perched along the outskirts of an idyllic village.

Climb around the high waterfalls on series of iron ladders and bridges within the wildest gorge in the Slovak Paradise.

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

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

A literally moving statue of stacked metal giants just continually trying (and failing) to find love.

This neon lit Georgian cave claims to hold the boulder Prometheus was chained to.

Nature's water park in the Wadi Bani Awf valley is full of pools flanked with cliffs and natural water slides.

This bazaar is one of the oldest in the Arabian world.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

A mesmerizing reservoir nestled at the heart of a pre-Islamic Yemeni village.

This hidden gem is bathed in beautiful natural light.

A charming beach town in Turkey captures all the colors of the rainbow.

Over the centuries, this island paradise has done it all, from providing monks with ecclesiastical respite to sheltering an exiled Leon Trotsky.

Fantastic lake on the heart of a fault line.

Roman ruins, natural methane fires and a lovely beach.

Ottoman-era houses lovingly preserved.

Hidden just under the waters around this Turkish island are the ruins of a once great city.

A Lycian city of the dead carved into the hillside of Southern Turkey, complete with startlingly human touches.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.