Was the Sahara a green and jungle-like place back then?
Not that recently, but it was at one time. I've seen some cave-drawings there depicting big game, trees, etc.
It wasn’t jungle like. However, it may not have been as dry and dead as it is today. The Sahel is losing its lakes and dying of “desertification” from over-grazing by goats and sheep. These cities may have been on the edge of dry grassland in their time before their livestock destroyed the grasses, causing the areas to dry up.