If you're into ancient civilisation, the sunken city of Simena where you encounter remains of Lycian civilisation is a must.
More information at LycianTurkey.com http://www.lycianturkey.com/lycian_sites/kekova_simena.htm
Address Çayağzı Yolu, Antalya Province, Turkey
Coordinates 36°12'4.859" N 29°57'37.56" E