Discusses the polio epidemics that swept the world in the early twentieth century, including interviews with victims of the disease, and chronicles the search for a vaccine which was ultimately developed by American doctor Jonas Salk in the early 1950s.
Examines the Great Wall of China, one of the most massive building achievements in history, discussing some of the myths and mysteries associated with the Wall, and looking at what modern engineers and historians have discovered about the structure.
