Which is the driest desert on Earth?

We all know that deserts are one of the driest places in the world but did you know that the Atacama desert in Chile is the driest? To understand what that really means let's take as an example the Sahara desert (the worlds largest hot desert) and note that it receives a meager 2mm of rain each year.
Just imagine how dry the Atacama is when it receives just 0.1mm per year. In fact some parts of the desert have not seen rainfall for over 400 years making it in most estimation the driest place on the planet earth.