when did the trans saharan trade routes begin
Trans-Saharan trade The Sahara once had a very different environment. In Libya and Algeria, from at least 7000 BC, there was pastoralism, the hearding of sheep, goats, large settlements, and pottery. Cattle were introduced to the Central Sahara (Ahaggar) from 4000 to 3500 BC. Remarkable rock paintings (dated 3500 to 2500 BC), in places which are currently very dry, portray vegetation, and animal presence rather different from modern expectations.[1]
Stockholm Water Prize 2006: Professor Asit K. Biswas, The Third World Center for Water Management
1 + 2 + 3 + 4 + ⋯ which increases without bound as n goes to infinity. Because the sequence of partial sums fails to converge to a finite limit, the series does not have a sum.
Bull riding The flank strap