Sillyon, a rugged ancient city waiting to be discovered, lies in the shadow of Perge and Aspendos. Perched on a high hill in the middle of the Serik Plain, it is one of Antalya’s lesser-known yet most striking ancient sites. Even Alexander the Great failed to conquer it, making Sillyon one of the most “inaccessible” and impressive ancient cities in Antalya.