Original: The cataracts of the Nile are shallow stretches of the river between Aswan and Khartum where the water 's surface is broken by numerous small boulders and stones protruding from the river bed , as well as many small rocky islets .
Simplified: In ancient times , Upper Egypt extended from the Nile Delta to the first cataract , while farther upstream , the land was controlled by the ancient Kush civilization , that would later take over Egypt .