Where are we:

The Grand Erg Oriental (Great Eastern Sand Sea) is a large erg (berber word for "field of sand dunes" part of the Sahara. The erg's northeastern corner spills over into Tunisia as it is mainly situated in the Saharan lowlands of northeast Algeria. It covers an area some 600 km by 200 km.

The Sahara (The Arabic word for “Desert”), with a size of 8.6 million km², is the world's largest hot desert and covers large parts of Northern Africa with a population of about 4 million.
At its maximum length, from the Atlantic Ocean in the west to the Nile River in the east it covers 4,800 km, and up to 1,200 km from the Atlas Mountains in the north to 16º northern latitude in the south. The Sahara covers most of Mauritania, Western Sahara, Algeria, Libya, Egypt, Sudan, Chad, Niger and Mali, and touches Morocco and Tunisia.