A marvel of Byzantine engineering under the streets of Istanbul.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.

Gargantuan home of Russian science.

Former headquarters of the KGB.

Thirteen sculptures in central Moscow graphically depicting vices of the modern world.

Moscow's imposing monument to the Space Age.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

Secret Swing.