Constantinople - now known as Istanbul - has changed significantly since it fell to the Ottomans in 1453. Domed mosques with minarets are now integral to its skyline, which now increasingly has skyscrapers as well. Underneath it all, though, the Byzantine influence can still be strongly felt. While Ottoman architects like Mimar Sinan developed their own styles, the dome, Byzantine in origin, still dominates the city. This can perhaps best be seen in the Byzantine churches of Constantinople, scattered across the old city. Hagia Sophia, the most famous building, was of course a church for almost a thousand years. It is in no way the only remaining church from the Byzantine Era. Of the many Byzantine churches remaining, most were converted into mosques, meaning their original art and decoration were lost or significantly altered - though fires and earthquakes had the greatest impact. The only one that was not converted into a mosque is the Church of Theotokos Mouchliotissa, while ​Hagia Eirene lost its religious function, but was used by the Janissaries and later was the city’s first museum. In addition, there are three churches that give us the best glimpse of how these former churches once appeared: Hagia Sophia, Chora, and Pammakaristos (now Fethiye Mosque). There are several other noteworthy churches, including Sergius and Bacchus, Pantokrator, and Theotokos Kyriotissa. We can also look to other cities, such as Thessaloniki, Ravenna and even Venice to understand how these former churches once appeared. In addition, there are several Byzantine churches in the hinterland of Constantinople, including several monastery caves - and there are pre-Ottoman churches in Galata as well.