Two things you might not expect to find if you visit the foothills of Mount Graham in eastern Arizona:
1) An elaborate network of "hanging canals" likely built nearly a thousand years ago on steep mesas by long-forgotten ancients.
2) An endearingly eccentric electrical engineer and author who, long before he started trying to solve the archaeological mystery, helped pioneer the world of personal computers.
Nevertheless, on a sunny morning, Don Lancaster wrestles his four-wheel-drive SUV over ruts and boulders into the bajada above the Gila River Valley.
His voice rising with excitement, the bearded 73-year-old urges passengers to hold tight and keep their eyes on the slope of a nearby butte.
"Right around this corner," he promises. "You won't miss it. One of the most spectacular of the hanging canals.... As far as I know, what we have here is unique in the Southwest -- and could be in the world."