The Atacama Desert stretches 960 kilometers (600 miles) south from the border of Peru and its average width is less than 160 kilometers (100 miles) wide between the Pacific Ocean and the Andes Mountains. It is basically a rainless plateau that is made up of salt lakes, lava flows and sand. It is noted to be the driest place on earth, with some places where no human has ever recorded a single drop of rain and with dry river beds that have not seen water in 120,000 years. The dryness of the desert and the abundant natural mineral resources provide the perfect environment for preservation. The land offers up relics and artifacts today, evidence of man's inhabitation of the desert for thousands of years. Some of the oldest mummies on earth have been found in the Atacama, one over 9000 years old. Huge geoglyphic paintings adorn the hillsides and ruins of Indian fortresses and sacred Inca sites dot the landscape.