Richat structure - geological formation, located in the western part of the Mauritanian Sahara desert in Africa. The diameter of the structure is 50 km away. For a long time, the structure Richat guide the astronauts in orbit as represented clearly visible object in the vast expanse of unremarkable desert. Before the start of the Space Age Structure Richat it was unknown, because it is the first time the astronauts discovered this huge eyes that looked straight at them.
It is believed that the structure of the most ancient ring Richat - 0, 5-0, 6 billion years. Previously it was assumed that the structure is an impact crater from a meteorite fall, but this hypothesis is not consistent with the shape of a flat bottom and a complete lack of rock with traces of impact. Education structure as a result of a volcanic eruption also seems highly unlikely due to the lack of a dome of igneous or volcanic rock. Currently, scientists believe that the structure Richat sedimentary rocks are the result of the erosion in the area picked up the earth's crust.