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A desert at 20N and 35E would be the Sahara desert. This is the largest desert in the world.
Africa
Karakum Desert
Only part of the Sahara Desert is found in Sudan (north Sudan). The Sahara Desert is vast and streaches through most north African countries.
See related question
There are 2 desert regions in southern Africa, namely the Kalahari desert region and the Namib desert region.