Understand
The river Nile narrows at Silsila in order to get through the relatively narrow gorge, composed of steep sandstone cliffs on either side, that it has cut in order to continue its journey far north to the Mediterranean Sea. The locality seems to have formed a natural obstacle to otherwise sedate river traffic, probably reflected in its ancient Egyptian name Khenu, translated as "the Place of Rowing".
Geologically, this gorge marks the point at which the underlying bedrock of Egypt changes from limestone to sandstone. The high quality sandstones at this locality, much in demand, were quarried for centuries during the Pharaonic period and - having been transported up and down the river - were employed in monumental structures the length of Egypt. By the later Ptolemaic and Roman periods, tens of thousands of workers were employed here each year quarrying building stone.
