Hagia Sophia, officially the Hagia Sophia Grand Mosque, is a mosque and a major cultural and historical site in Istanbul, Turkey. The cathedral was a Greek Orthodox church from 360 AD until the conquest of Constantinople by the Ottoman Empire in 1453.

The Maiden's Tower (Turkish: Kız Kulesi), also known as Leander's Tower (Tower of Leandros) since the medieval Byzantine period, is a tower on a small islet at the southern entrance of the Bosphorus strait 200 m (220 yd) from the coast of Üsküdar in Istanbul, Turkey.

The Galata Tower (Turkish: Galata Kulesi), called Christea Turris (the Tower of Christ in Latin) by the Genoese, is a medieval stone tower in the Galata/Karaköy quarter of Istanbul, Turkey, just to the north of the Golden Horn's junction with the Bosphorus.