Yeşilköy (Turkish pronunciation: [jeˈʃilcøj]; prior to 1926, San Stefano or Santo Stefano from the Greek: Άγιος Στέφανος pronounced Ayos Stefanos, rendered in Turkish as Ayastefanos, Bulgarian: Сан Стефано) is a neighbourhood (Turkish: mahalle) in the district of Bakırköy Istanbul, Turkey. It is located along the Marmara Sea about 11 kilometres (7 miles) west of Istanbul's historic city centre. Before the rapid increase of Istanbul's population in the 1970s, Yeşilköy was merely a village and a sea resort.