What is the driest hot desert in the world?

The Atacama in northern Chile, where some weather stations have recorded no rainfall at all across their entire operating life, and riverbed evidence suggests centuries at a time with essentially none. It sits in a double rain shadow: the Andes block moisture from the Amazon, and a cold current offshore stops the Pacific delivering any.

The qualifier hot is doing necessary work, because by pure lack of precipitation the McMurdo Dry Valleys in Antarctica are comparable or drier - parts of them may not have seen rain for two million years. The Atacama usually takes the general title because people expect a desert to be hot and sandy.

It behaves like another planet, which is exactly what it gets used for: NASA tests Mars instruments there, and some soil samples have been so sterile that standard detection methods found no life at all. It is also where the Chinchorro people were mummifying their dead two thousand years before the Egyptians - the ground did most of the work - and where, in 2015, an unusual rain event produced a bloom of flowers from seeds that had been waiting in the soil for years.