Using original source footage, this program examines several major disasters, including the space shuttle Challenger, and discusses the scientific principles behind the engineering failures. Analyzing each project, a professional engineer uses practical demonstrations to illustrate the miscalculations that cause bridges to collapse, the fuselages of planes to crack, and the roofs of a newly built hotel and a stadium to give way. The program illustrates a series of tests that can predict project failures. The efficiency of modern computer engineering design is compared with that of traditional engineering methods that require more decision-making and risk on the part of engineers. Original BBC broadcast title: To Engineer Is Human. (51 minutes)