This week's edition of The Revealer on BackStory takes us to the bustling metropolis of Istanbul. Turkey's largest city is home to the spectacular Hagia Sophia monument, considered one of the finest examples of Byzantine architecture. The building began life as a Christian church, but became a mosque during the Ottoman Empire.
The Hagia Sophia is now a museum visited every year by more than two million people. Many visitors think they know everything there is to know about the building. But, a Byzantine expert takes us on a tour revealing many of the museum's little-known secrets, many of which are hidden in the building's beautiful mosaics.