Although it is not completely certain as to when the Galata Tower was built, it is claimed that the it was built during the reign of the Byzantian Emperor, Iustinianos in 507 CE.
It was called the Christea Turris (Tower of Christ) by the Genoese and the Megalos Pyrgos (The Great Tower) by the Byzantines. It took its present shape during the Genoese period. The Tower was heavily damaged during an earthquake in 1509, and it was renewed by the architect, Hayrettin, who was very famous during that period. During the reign of Süleiman the Magnificent (1520-66), it was used as a jail for prisoners who were sentenced to work at the Kasımpaşa Naval Dockyard. The head astrologer, Takıyeddin Efendi, established an observatory on the top of the tower at the end of the 16th century and functioned as an observatory for a particular period of time. Later, it was closed and again turned into a prison by Sultan Murat III (1546-1595). After it was repaired, a cumba, a little room made of wood, was added to the tower during the reign of Sultan Selim III (1761-1808). After another fire in 1831, Sultan Mahmut added two more floors to the Tower and covered the top of the tower with a famous cloth in the shape of a conical hat. After passing though the restaurant on the top floor, there is a balcony that encircles the tower. The restaurant’s view showcases a scene of Istanbul and the Bosphorus.