Grand Erg Occidental
Appearance
There is not a way any human life could be sustained here. There are no villages inside it, and no roads through it. The Grand Erg Oriental (Eastern Sand Sea) and the Grand Erg Occidental (Western Sand Sea) take up a great part of northern Algeria and they are just 2 of close to 20 such Saharan sand seas whose sands in some parts are over 300m deep.
http://www.bbc.co.uk/nature/programmes/tv/wildafrica/granderg.shtml