Maiden's Tower, also known as Kız Kulesi in Turkish, is a small tower located on a tiny islet in the Bosphorus Strait in Istanbul, Turkey. The tower has a history dating back to the 5th century, and it has served various purposes throughout its history, including as a lighthouse, watchtower, quarantine station, and even a prison.

The exact origins of the tower are not clear, but it is believed to have been built by the ancient Athenians during their period of domination in the region, although it has undergone many renovations and modifications over the centuries. During the Byzantine period, the tower was used as a customs checkpoint and later as a defense tower against invading armies.

During the Ottoman period, the tower served as a quarantine station for ships arriving from abroad. It was also used as a lighthouse to guide ships through the Bosphorus Strait.

One of the most famous legends associated with the Maiden's Tower is the story of a sultan who was warned by a soothsayer that his daughter would die from a snake bite. To protect her, the sultan built the tower in the middle of the Bosphorus Strait and placed his daughter inside. Unfortunately, a snake hidden in a fruit basket delivered to the tower did bite her and she died. This legend has given rise to the tower's nickname, "The Maiden's Tower".

Today, Maiden's Tower is a popular tourist attraction in Istanbul. Visitors can take a boat ride to the tower and climb to the top to enjoy panoramic views of the city and the Bosphorus Strait. The tower also houses a restaurant where visitors can enjoy a meal with a view of the surrounding water.