KwaZulu-Natal (pronounced /kwɑːˌzuːluː nəˈtɑːl/, also referred to as KZN or Natal) is a province of South Africa. The province has three different geographic areas. The lowland region along the Indian Ocean coast is extremely narrow in the south, widening in the northern part of the province. The central region is the Natal Midlands and is an undulating hilly plateau rising towards the west. Two mountainous areas, the Drakensberg Mountains in the west and the Lebombo Mountains in the north. The Drakensberg is a solid wall of basalt rising over 3,000 m (9,800 ft) skyward near the Lesotho border, whilst the Lebombo Mountains are ancient granite mountains forming low parallel ranges running southward from Swaziland. The Tugela River flows west to east across the center of the province and is the region's largest river. KwaZulu-Natal has a varied yet verdant climate thanks to diverse, complex topography. Generally, the coast is subtropical with inland regions becoming progressively colder.