Built in 537 by the Roman Emperor Justinian, Hagia Sophia which means Church of the Holy Wisdom was at one time the largest domed indoor structure in the world.
After the fall of Constantinople to the Ottoman Empire in 1453, Hagia Sofia was converted into a mosque and it remained one until 1931 when the now Republic of Turkey deemed it a museum under the leadership of Ataturk.
In July 2020, the Hagia Sophia was once again deemed a mosque after the 1931 decision was overturned. The mosque welcomes visitors during non-prayer times. Women must have their heads covered to enter so be sure to bring a scarf.