The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

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

A war-torn Olympic relic is being overtaken by graffiti and nature.

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

Bridge that died in war and was resurected.

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

A sinuous path among steep cliffs creates a stunning sight in southwestern Serbia.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

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

Structure built from the skulls of vanquished foes.

Legends of treasure and spirits flow from this this fairy tale-like oasis.

An abandoned 1970s theme park that has been turned into a space for waterfront walking.

The longest enclosed pedestrian bridge in the world spans 14 lanes of traffic and six rail tracks, all while lighting up the night sky.

This former big box store has been reimagined as a massive public art space.

A Canadian POW for German soldiers during WWII where prisoners hatched an elaborate escape plan.

Canada's oldest railway tunnel is illuminated in a rainbow of color as it passes under the streets of this small city.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

America's oldest drive-in movie theater has been in continuous operation since 1934.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

One of the most accessible undersea plane wrecks in the world.

In paradise, feral pigs have claimed an island all to themselves.

This spaceship-like Serbian monument reaches for the stars in celebration of the fallen fighters of fascism.

An abandoned logging settlement nestled in the woods near a popular ski town.

The remains of a Canadian train crash are now mouldering beneath layers of rust and graffiti.