The delta, which is where a river opens into the sea, is called a delta because, as you can see, these rivers, you can even see it from the satellite pictures right over here, they start branching up a bunch, and you have this upside-down triangular region, which looks a little bit like an upside-down Greek letter delta. So that's why a river delta is called that. And this one just happens to be upside-down. If it was flowing the other way, it would be a right-side-up delta. So the Nile River, it flows from, you could say, eastern Mid-Africa up into the Mediterranean Sea. And because it has this northward flow, the southern parts of the river are upriver, and they are actually called the Upper Nile. So the Upper Nile is actually south of the Lower Nile.