The Libyan Desert forms the northern and eastern part of the Sahara Desert. It describes that part of the Sahara that lies within the present-day state of Libya; it also historically describes the desert to the south of Ancient Libya, a territory which lay to the east of the present-day state. The Libyan Desert is one of the driest, harshest and most remote parts of the Sahara, the world's largest hot desert. This extended desert country is barren, dry and rainless. Modern Libya is divided into the regions of Cyrenaica, Tripolitania and the Fezzan. The country covers an area of 1,760,000 square kilometres (680,000 sq mi). most of which is desert save for a narrow coastal strip to the north on the shore of the Mediterranean, and the mountains of Cyrenaica (the Jebel Akhdar, or "Green Mountains"). The desert covers an area of approximately 1,100,000 square kilometres (420,000 sq mi), and extends approximately 1,100 km from east to west, and 1,000 km from north to south, in about the shape of a rectangle slanting to the south-east. Like most of the Sahara, this desert is primarily sand and hamada or stony plain. Sand plains, dunes, ridges, and some depressions (basins) typify the endorheic region, with no rivers draining into or out of the desert. The Gilf Kebir plateau reaches an altitude of just over 1,000 m, and along with the nearby massif of Jebel Uweinat is an exception to the uninterrupted territory of basement rocks covered by layers of horizontally bedded sediments, forming a massive sand plain, low plateaus, and dunes. The desert features a striking diversity of landscapes including mountains, oases, and sand seas.