Considered to be a symbol of Istanbul, this tiny tower was established on a small island at the entrance of the Bosphorus. In the past, Kiz Kulesi was used as a watchtower and a lighthouse, until its present purpose of a tourist attraction. Western sources describe this as Leander’s Tower, who was drowned while swimming, to reach his lover Hera.
Another story suggests that Kiz Kulesi was a tower where an emperor’s daughter put her in there for security, having dreamt that she would be bitten by a snake.
Source: Republic of Turkey Ministry of Culture ans Tourism