The old Tower of Galata (Greek: Megalos Pyrgos, meaning Great Tower) was a tower which stood on the north side of the Golden Horn in Constantinople, inside the citadel of Galata. The tower marked the northern end of the great chain, which was stretched across the mouth of the Golden Horn to prevent enemy ships from entering the harbor. The tower contained a mechanism for raising and lowering the chain.
The tower was largely destroyed by the Latin Crusaders during the Sack of Constantinople in 1204, part of the Fourth Crusade, enabling them to enter the harbor and attack the city from the sea, where the walls were more easily scaled.
This tower should not be confused with the present-day Galata Tower, which is still standing. The current tower was built by the Genoese in 1348, on a different site, at the northernmost and highest point of the citadel of Galata.
The Genoese named the new tower as Christea Turris (Tower of Christ). The Byzantines, however, also called this new tower with the name Megalos Pyrgos (Great Tower).