The first cataract of the Nile River is at Aswan, Egypt. Aswan is identified with Syene in Ezekiel 29:10, and with the Sinim of Isaiah 49:12. This cataract provided a natural boundary between Egypt to the north and Cush to the south. It was impossible for large boats to traverse this region of the Nile.
The first cataract of the Nile River at Aswan, Egypt. Photo by Ferrell Jenkins.
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Ferrell's Travel Blog 
A wonderful post. Thank you.