It was established in 1935 as a semi-open prison and is a witness to several memorable moments in Turkish history. Following the Turkish military coup in 1960, ex-Prime Minister Adnan Menderes was imprisoned on the island. After the death sentences delivered at the Yassıada trials, on Yassiada island, the ex-Foreign Minister Fatin Rüştü Zorlu and ex-Finance Minister Hasan Polatkan were both hanged on the 15 September 1961 while Menderes was hanged two days later. After February 1999, the leader of the Kurdistan Workers Party (PKK) Abdullah Öcalan was captured, the island was vacated and placed within a military zone. In November 2009, a new detention facility was inaugurated, to which Öcalan and five other prisoners coming from mainland Turkey were transferred.