The Atacama desert runs along the western edge of South America, squeezed between the Andes mountains and the cold Pacific Ocean. That double barrier blocks moisture from both sides, leaving the Atacama as the driest place on Earth outside of the polar regions.
Some weather stations there have never recorded a single drop of rain. The dry conditions are so similar to Mars that NASA uses parts of the desert to test its Mars rovers and search for the kind of tiny tough microbes that might survive on other planets.
The dry air is also amazing for stargazing - the world’s biggest telescopes are perched on Atacama mountains, peering at galaxies through some of the clearest skies anywhere. And because nothing rots in the dry sand, the desert preserves natural mummies thousands of years older than the famous Egyptian ones.
