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

One of downtown Berlin's last reminders of its Communist past.

For patriotic Russians, this memorial honoring the Soviet soldiers who died liberating Berlin in 1945 is the most sacred location outside of Russia.

You'll find just about anything in this funky Tbilisi flea market.

The secret room where early Bolsheviks cranked out propaganda fliers on a smuggled printing press.

At this rare mosque in Tbilisi, Sunni and Shia Muslims pray side by side.

When the Soviets destroyed the historic Armenian monastery they somehow left its bell tower intact.

Unusual building appears to be haphazardly built from randomly piled bricks.

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

With over 10,000 lights, this engineering marvel lights up the city after dark.

This architecturally eclectic fortress witnessed centuries of bloody turmoil, including the massacre of its ruling clan.

These Stalin-era industrial 'death traps' hang lifeless above the city

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

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

A cylinder monument with a spectacular vista commemorates a friendship that some say never existed.

A model memorial to the original Odin Tower, the second highest tower in Europe before it was sabotaged by Danish Nazis.

Looking for a unifying history, Uzbekistan finds its answer in a 14th Century Turco-Mongol conqueror... despite the fact he wasn't Uzbek.

An 18-meter-long sarcophagus of a constantly growing dead prophet.

Light still pours into the ruins of this ancient Islamic observatory.

The Avenue of Mausolea is a series of grand palatial tombs.

An underground world of gorgeous, palatial metro stations designed as a nuclear shelter complex.

This risqué sculpture, based on a Hans Christian Andersen fairy tale, caused outrage 35 years after it was erected.

The only castle in North America to ever house European sovereigns.

This incredible college library is a visual masterpiece of mosaic art. It also looks kind of like a giant boombox.