For thousands of years, the Nile River has provided the 'life blood' to Egypt. Stretching over 800 miles, the world's longest river brought fresh water to all within reach of its valleys, and delivered fertile silt from the steppes of Ethiopia to the coastal delta of the Mediterranean Sea. Its seasonal flooding fertilizes and cleanses the surrounding lands allowing inhabitants to farm what would otherwise be non-arable acreage. Without this flooding, only 15,000 of the 383,000 square miles of arid Egyptian land would be able to support human life. To survive, flood control and irrigation were the basis of the earliest civilizations within Egypt. Thus, the planning for the Aswan Dam began.