This historic stone bridge has an entire neighborhood clinging to its sides.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

The fairy tale castle of the "fairy-tale king."

Stone Age solar temple is aligned with the sun on each equinox and solstice.

An intimate look into the apartments of Jounieh via cable car.

The largest hewn stone in history.

The world's oldest map of the holy land gives us a fragmented glimpse of the layout of biblical nations.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

Only a handful of these gorgeous historic waterwheels remain but even those are in danger from local unrest.

Mysterious lost empire of the Silk Road.

This Armenian monastery was carved out of cliffs and named after the spear used to stab Jesus.

Tower with a double-helix spiral, adorned with letters of the Georgian alphabet.

Take respite inside this jaw-dropping church while climbing the volcano where Georgia's Prometheus was once chained.

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

Luxury hotel turned into a refugee camp, then turned back into a luxury hotel.

A museum glorifying the life of Stalin, located in the city of his birth.

The charmingly disheveled clock tower of Tbilisi's puppet theater.

Ancient rock-hewn town that witnessed key events of Georgian history.

Rock-hewn monastery complex with hundreds of cave structures tucked away into the mountainside.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.