"10 Routes that Crossed the World explores the history, geography, and environmental and social impact of 10 significant routes or trails around the world. The routes included are: the Bering Strait land crossing, Roman roads in Britain, the Camino de Santiago, Inca trails, the Khyber Pass, the Trans-Siberian Railway, Chilkoot Pass, the Serengeti migration trail, U.S. Route 66, and the Ho Chi Minh Trail.".