A rift valley is created when two tectonic plates pull away from each other, leaving a low space in the middle. The Great Rift Valley is the best known rift valley in the world. It covers a distance of over 6,000 kilometres (3,700 miles), stretching from northern Syria in West Asia to central Mozambique in East Africa. It began to form about 35 million years ago, when the African and Arabian tectonic plates began to pull apart. Even today it is still growing, as East Africa slowly separates from the rest of Africa.