Late summer in Egypt, around 2525 B.C., and the Nile is flooding. To a worker named Merrer, the deluge means it is time to bring stone to the site of Pharaoh Khufu's pyramid. The journey from the quarry in Tura southeast of the port at Giza is just eight miles. But the heavy cargo of gleaming white limestone, which will form the outer layer of the monument, makes the crafts difficult to maneuver. And the river seems as vast as an ocean when it rises over its banks. Merrer has sailed the open seas before, however. The fleet of barges and the 50 men under his command are in experienced hands.