The mountains There are numerous inactive volcanoes in the region including Nemrut, Suphan, Tendurek and Turkey's highest peak, Mount Agri (Ararat), which is 5,165 metres high. At the same time, several plains extend along the course of the River Murat, a tributary of the Firat (Euphrates). These are the plains of Malazgirt, Mus, Capakcur, Uluova and Malatya. The Southeast Anatolia region is notable for the uniformity of its landscape, although the eastern part of the region is comparatively more uneven than its western areas. Rivers Most of the rivers of Turkey flow into the seas surrounding the country. The Firat (Euphrates) and Dicle (Tigris) join together in Iraq and flow into the Persian Gulf. Turkey's longest rivers, the Kizilirmak, Yesilirmak and Sakarya, flow into the Black Sea. The Susurluk, Biga, and Gonen pour into the Sea of Marmara, the Gediz, Kucuk Menderes, Buyuk Menderes and Meric into the Aegean, and the Seyhan, Ceyhan and Goksu into the Mediterranean. Lakes In terms of numbers of lakes, the Eastern Anatolian region is the richest. It contains Turkey's largest, Lake Van (3.713 square kilometres), and the lakes of Ercek, Cildir and Hazar. There are also many lakes in the Taurus mountains area the Beysehir and Egirdir lakes, and the lakes that contain bitter waters like the Burdur and Acigoller lakes. Around the Sea of Marmara are the lakes of Sapanca, Iznik, Ulubat, Manyas, Terkos, Kucukcekmece and Buyukcekmece.