Dominated economically by the sprawling city of Pátra , the large province of Ahaïa combines high mountains and a narrow, densely populated coastal strip; from Dhiakoftó in the north, one of Greece's most remarkable railway lines follows the Vouraikós Gorge, up to the memorials of Kalávryta . To the southwest of Ahaïa, the flat coastal plains of Ilía support a series of undistinguished market towns and are bordered on the west by long, narrow, often underused beaches. The Olympia archeological site is the jewel of the fertile Alfíos valley and this area's main tourist attraction.