The River Kwai is a river in western Thailand that is best known for its historical significance during World War II. In 1942, the Japanese built a railway bridge over the river as part of the Burma Railway, a strategic supply route to Burma. The bridge, which was completed in 1943, was the scene of a battle in 1945 between Allied forces and the Japanese, which was later immortalized in the 1957 movie, The Bridge on the River Kwai. Today, the bridge is a popular tourist destination, and the River Kwai is a popular destination for rafting, kayaking and other water-based activities.