The Ethiopian Highlands form the largest continuous area of its altitude in the whole of Africa, with little of its surface falling below 1,500 meters. The range was formed by the Great Rift Valley's tectonic activity and volcanic eruptions millions of years ago. It is the source of the Blue Nile, which provides the majority of the Nile River's water. The highlands are home to unique biodiversity, including the endangered Gelada baboon and the Ethiopian wolf. Because of its elevation, the region has a much cooler and wetter climate than the surrounding lowlands, allowing for the cultivation of coffee, which originated in this region's forests. The rugged terrain has historically protected Ethiopia from colonization, making it one of the few African nations to maintain its independence.