Grand Erg Oriental follow the wind's direction. There are other types of dunes, as well as "complex" dunes. Saharan winds are also known to clear an area of sand altogether, leaving bare rock (hamada) or gravel (reg). The "Grand Erg Oriental" is accessible overland by an Algerian road, which goes south from Constantine. It passes through the Aurès mountains, then salt lakes by the city of Biskra. Next the road skirts the western edge of the erg. After about 500 km. in all, it reaches the ancient oasis of Ourgla [Wargla]. Since late antiquity Wargla was a stop for the Saharan trade, being
Is Geography Destiny? Is Geography Destiny? Is Geography Destiny? Lessons from Latin America is a book written by John Luke Gallup, Alejandro Gaviria, Eduardo Lora and published by the Inter-American Development Bank (IDB), which documents an advanced step of the rediscovery of geography by economists initiated by Paul Krugman in the early 1990s, however in another, more deterministic direction. Inspired by the works of David Landes, Jared Diamond and Jeffrey Sachs, considered as “champions of the rediscovery of geography”, the book is the result of “a series of studies on the influence of geography on Latin American development”. It is part of the