Kwai Noi River , The river is chiefly known from the Pierre Boulle novel and David Lean film The Bridge on the River Kwai, in which Australian, Dutch and British prisoners of war were forced by the Japanese to construct two parallel bridges spanning the river as part of the Burma Railway, also called the Death Railway for the many lives lost in its construction. One bridge was wooden and temporary. The other was made of concrete and steel and still exists. Ironically, the bridges actually spanned the Mae Klong, but as the railway subsequently follows the Khwae Noi Valley, the bridges became famous under the wrong name. In the 1960s, the upper part of the Mae Klong was renamed the Khwae Yai