The Princess Island tour (Kızıl Adalar or just Adalar) are a chain of nine rather small islands in the Sea of Marmara. They evolved from a place of exile during the Byzantine era, to a popular destination for tourists and Istanbulites alike to escape the hectic city life for a day. Of those nine islands, only four of them are open to the public: Büyükada, the biggest and most popular, Burgazada, Heybeliada and Kınalıada.