The driest location on Earth is the Atacama Desert in Chile. This area receives on average less than 0.004 inches of rainfall per year, as it sits in the rain shadow region west of the Andes. Within the Atacama Desert, the abandoned mining town of Yungay is driest.
This is due to the area's position, screened from moisture from the Pacific by a lower mountain range as well as from the Amazon rain forest by the Andes. Scientists believe that the Atacama Desert has maintained its extremely arid environment for at least 3 million years, making it one of the oldest and driest regions on the planet.