A little distance offshore from the coast of Djibouti, the northern extent of Africa's Great Rift Valley abuts a triple junction where the oceanic rifts of the Red Sea and the Gulf of Aden converge. In this infertile coastal region of unstable geology, the rift widens perceptibly each year. This aerial photograph shows an obvious crack in a huge lava ridge. Other than Iceland, Djibouti is the only country where scientists can observe the sea floor spreading on dry land as two plates move apart.