Discover the ancient ruins of Constantinople in Istanbul Old City. Explore Sultanahmet and learn about the Byzantine history and legends, the last era of the Roman Empire. Extended options: private tour of Hagia Sophia and the Basilica Cistern. Choose one of our excellent tour options tailored to your needs and interests: 2-hour: The Byzantine Empire Tour of the Old City Explore the Sultanahmet Old City and discover the history of the Byzantine Empire. See the Hippodrome, Hagia Sophia (outside only), and more. 3-hour: Old City & Hagia Sophia Visit the Hagia Sophia Mosque, explore the Sultanahmet Old City and discover the history of the Byzantine Empire. See the ancient Hippodrome and more highlights. 4-hour: Old City, Hagia Sophia & Basilica Cistern Visit the Basilica Cistern and Hagia Sophia, explore the Sultanahmet Old City and discover the history of the Byzantine Empire, including the ancient Hippodrome.