Does anyone also know--I remember reading somewhere that within historical memory, the arable area of Egypt was greater, and that within recorded history, the Sahara has expanded from the west, covering land that was once fertile and inhabited. That is, in the past, it wasn't just the narrow strips of land along the Nile that were cultivated, but those regions stretched further away from the river. I don't recall any mention of that in the show, but some of the digs that they showed might tend to support that.
Prost!
Bradley