 In this deep trough lies Lake Malawi (also called Lake Nyasa), the third-largest lake in Africa, comprising about 25% of Malawi's area.Lake Malawi is sometimes called the Calendar Lake as it is about long and wide.The surface of Lake Malawi is located at above sea level, with a maximum depth of , which means the lake bottom is over below sea level at some points.The Shire River flows from the south end of the lake and joins the Zambezi River south in Mozambique.