Gli is a cross-eyed adorable cat that has been living in Hagia Sophia for the past 15 years. Hagia Sophia, also called Church of the Holy Wisdom or Church of the Divine Wisdom, cathedral built at Constantinople (now Istanbul, Turkey) in the 6th century CE under the direction of the Byzantine emperor Justinian I. By general consensus, it is the most important Byzantine structure and one of the world's great monuments. The Hagia Sophia is more than 2,000 years old and is one of the most extraordinary structures ever built. It has been a temple, church, mosque, and museum throughout its long history.