The Driest Place On Earth Background: The Atacama Desert is a virtually rainless plateau made up of salt basins (salares), sand, and lava flows, extending from the Andes mountains to the Pacific Ocean. The total area of the Atacama is 181300 square-km. The Atacama Desert is the driest place on Earth and is virtually sterile because it is blocked from moisture on both sides by the Andes mountains and by coastal mountains. The average rainfall in the Chilean region of Antofagasta is just 1 mm per year, and there was a period of time where no rain fell there for 400 years (1570-1971). While some locations in the Atacama do receive marine fog to provide sufficient moisture for hypolithic algae, lichens and even some cacti, the soil in many other areas has been compared to that of Mars, with experiments unable to detect any signs of life in the desert soil. The three pictures are glimpses of Valle de la Luna (Valley of the Moon), located a few kilometers outside oasis town San Pedro de Atacama (alt 2400m). Chile