A group of U.S. and European motorcyclists churn along on a dirt byway in remote western China during a tour of attractions along the region's historic Silk Road. An Austrian firm offers the tour only in the fall and the spring, in deference to its physical challenges -- changes in elevations from sea level to 13,400 feet or more, and in temperature from zero to 120 degrees.
(Claude Pauly / November 29, 2007)