During World War II, Allied POWs were forced by Japanese Soldiers to work on the construction of the Thailand to Burma railway which included the Bridge on the River Kwai. The prisoners worked under savage conditions and only with basic tools. Based on witness testimonies and photographic evidence, the documentary tries to answer the questions as to how this feat of engineering was built. The documentary special also tells of the development of America's first precision guided munition, the' Azon' bomb, and how it was used to destroy the bridge.

• National Geographic