The Atacama Desert is famous for being the driest place on the planet. Due to its position between the Chilean Coastal Range and Andean Mountains it sits in rain shadows from both the East and West. These hyper-arid condition have persisted for 200 million years or more, also making it the oldest desert on Earth. Most areas have not seen notable rainfall within the last 500 years or so. Unsurprisingly, it is often compared to the surface of Mars, and in fact NASA uses it to test instruments for its Mars rovers.
The desert does however contain rich deposits of copper and sodium nitrate (which Chile and Bolivia fought over in the late 19th century). Also, due to its high altitude, extremely dry air, and lack of light pollution, the Atacama is also utilized as one of the most important locations for astronomical observation in the world. Many countries and space agencies operate some of the largest telescopes in the world here.