Updated at 2:15 p.m. ET
Turkish President Recep Tayyip Erdogan has ordered the Hagia Sophia museum, one of Istanbul's most famous landmarks, to be converted into a mosque.
He made the announcement on Friday, hours after a top court cleared the way for him to make the change.
The Hagia Sophia, a major draw for tourists, has a long and complicated history. The architectural marvel was built as a church by the Byzantines in the 6th century and then converted to a mosque after the Ottoman conquest of Constantinople in 1453.