Istanbul Travel Guide (Unabridged‪)‬

With its long history at the center of empires, Istanbul offers a wealth of historic and religious places to take in. The bulk of these ancient monuments, dating back to Roman, Byzantine, and Ottoman periods, including the Hagia Sophia, Topkapı Palace, Sultanahmet Mosque (Blue Mosque), and Basilica Cistern are located around Sultanahmet Square, while some others are dispersed throughout the peninsula of old city, such as Church of St. Savior in Chora (Kariye Müzesi), the entire inside of which is covered by mindblowing frescoes and mosaics. An impressive section of mostly intact Theodosian walls, which mark the full length of western boundary of the peninsula, is right next to this particular church.