So it starts in what today would be Ethiopia, Tanzania, kind of the highlands of central eastern Africa and it runs its 4,000 mile journey into the Mediterranean Sea. But Egypt isn't going to be able to use all of that Nile because there are points in the Nile which are kind of impassable at that point. It's called the first cataract which is about 750 miles south of the Mediterranean Sea. And this cataract, which is basically jagged cliffs and boulders and rapids, is really going to form the starting point for Egyptian society. Now the Nile is generally divided along that 750 mile strip in Egyptian civilization into two sectors. You have what's called the upper Nile and the upper Nile which is highlighted right there is actually in the lower portion of Egypt. But that's going to be characterized really by a thin strip of fertile soil surrounding that river.