Zambia takes its name from the Zambezi River, which rises in the north-west corner of the country and forms its southern boundary. This landlocked country lies between the latitudes 10o and 18o South and longitudes 22o and 33o East.It's neighbours are: Congo DR to the north and north west, Tanzania to the north east, Malawi to the east, Mozambique to the south east, Zimbabwe to the south, Botswana and Namibia to the south west and Angola to the West.Zambia's 752,000 square kilometres makes it a large country about the size of France, the Netherlands, Belgium and Switzerland combined. It consists for the most part of a high plateau, with an average height of between 1060 and 1363 meters above sea level. (3500 and 4500 ft). Isolated mountain ridges rise to more than 6000 ft with an occasional peak above 7000 ft on the eastern border, called Nyika Plateau. Over most of the country the surface tends to be flat, broken by small hills, the result of countless ages of undisturbed erosion of the underlying crystalline rocks. These rocks contain the bulk of the country's wealth in the form of minerals, and the 90 mile long corridor known as the Copperbelt, along the north-western part of the country, is the mainstay of the Zambian economy.The level of the land falls southward from the Congo DR / Zambezi divide in the north towards the Zambezi depression in the South. The plateau is broken by the huge valleys of the Upper Zambezi and its major tributaries, of which the Kafue and Luangwa Rivers are the largest. One result of the plateau formation of Africa generally is the swift discharge of water towards the coast and the interruption of the rivers by waterfalls and rapids. This has made them of little value for transport over their length, but very suitable for hydroelectric schemes and white water rafting adventures.With the exception of the Northern and Luapula Provinces which are part of the Congo DR basin, Zambia lies on the watershed between the Congo DR and Zambezi River systems. The three great natural lakes of the country, Bangweulu, Mweru and the southern end of Lake Tanganyika are all in the north and are part of the headwaters of the Zaire River. Lake Tanganyika is the second deepest natural lake in the world.Lake Bangweulu, which with its swamps covers an area of about 3800 square miles, is drained by the Luapula River. This river starts flowing south, then turns west and northwards to pass through Lake Mweru on its way to Congo DR.Along the southern border of the country stretches Lake Kariba, the largest man-made lake in Africa and the second largest in the world. It is about 280kms long and 40kms across at its widest point.