Overview

From ancient times, the existence and survival of Egypt has depended on the Nile River. About 4,000 miles (6,437 km) long, the Nile is the longest river in the world and consists of two main branches. The longer branch, often referred to as the White Nile, rises from the heart of central Africa and flows more than 3,000 miles (4,828 km) to the Sudan, where it is joined by the Blue Nile. At this junction, the two tributaries form the greater Nile, which then courses through Egypt and drains at the wide Nile Delta into the Mediterranean Sea.

The ancient Egyptians probably knew that the source of the Blue Nile was Lake Tana in Ethiopia, but the headwaters of...