The Republic of Mali, the largest country in west Africa, has Algeria to the northeast; Niger to the east; Burkina Faso, Côte d'Ivoire and Guinea in the south; and Senegal and Mauritania in the west. The country, which extends across the Tropic of Cancer, has a surface area of 1.24 million km2 and population of some 12.3 million (of whom around 1.1 million live in the capital, Bamako). Mali has a varied landscape, with a large part of the central area being characterised by a low plain around the Niger river. This forms the Macina region, where fl oods are common. In the south, ancient rock terrains mark the border with Côte d'Ivoire, while, in the west, the capital is situated on a plateau. The Hombori mountain range in the centre of the country culminates in Hombori Tondo (1,155 m). The northeast of Mali represents the southern extent of the Sahara desert, with the Adrar des Iforas plateau averaging a height of 600 m. The flfl oodplain of the Taoudenni dominates the north. The south and centre of Mali are irrigated by two rivers: the Senegal (formed by the confl uence of Bafing and Bakoy) and the Niger (whose source is in Guinea at Fouta-Djalon). The north is largely a desert zone.