American researchers have discovered the world's oldest paved road, a 4,600-year-old highway. (16)It linked a stone pit in the Egyptian desert to waterways that carried blocks to monument sites along the Nile. The eight-mile road is at least 500 years older than any previously discovered road. It is the only paved road discovered in ancient Egypt, said geologist Thomas Bown of the United States Geological Survey. He reported the discovery on Friday. "The road probably doesn't rank with the pyramids as a construction feat, but it is a major engineering achievement," said his colleague, geologist James Harrell of the University of Toledo. "Not only is the road earlier than we thought possible, we didn't even think they built roads." (17)The researchers also made a discovery in the stone pit at the northern end of the road: the first evidence that the Egyptians used rock saws. "This is the oldest example of saws being used for cutting stone," said Bown’s colleague James Hoffmeier of Wheaton College in Illinois.

"That's two technologies we didn't know they had," Harrell said "And we don't know why they were both abandoned." The road was discovered in the Faiyum Depression, about 45 miles southwest of Cairo. Short segments of the road had been observed by earlier explorers, Bown said, but they failed to realize its significance or follow up on their observations. Bown and his colleagues stumbled across it while they were doing geological mapping in the region. (18)The road was clearly built to provide services for the newly discovered stone pit. Bown and Harrell have found the camp that housed workers at the stone pit. The road appears today to go nowhere, ending in the middle of the desert. When it was built, its terminal was a dock on the shore of Lake Moeris, which had an elevation of about 66 feet above sea level, the same as the dock. Lake Moeris received its water from the annual floods of the Nile. At the time of the floods, the river and lake were at the same level and connected through a gap in the hills near the modern villages of el-Lahun and Hawara. Harrell and Bown believe that blocks were loaded onto barges during the dry season, then floated over to the Nile during the floods to be shipped off to the monument sites at Giza and Saqqara.