Kanchanaburi, in Myanmar border, is home to the famous Bridge River Kwai. During WW II, Japan constructed the meter-gauge railway line from Ban Pong, Thailand to Thanbyuzayat, Burma. The line passing through the scenic Three Pagodas Pass runs for 250 miles. This is now known as the Death Railway.

The railway line was meant to transport cargo daily to India, to back up their planned attack on India. The construction was done using POWs and Asian slave laborers in unfavorable conditions. The work started in October 1942 was completed in a year. Due to the difficult terrain, thousands of laborers lost their lives. It is believed that one life was lost for each sleeper laid in the track.

Allied Forces bombed the iron bridge in 1944. Three sections of Bridge River Kwai were destroyed. The present bridge has two of its central spans rebuilt. The original parts of the bridge are now displayed in the War Museum.

Bridge River Kwai is a tourist destination now. The track is developed into a walkway with side platforms. This allows crossing the railway bridge on foot. These platforms are useful as viewpoints and for avoiding trains. A small tourist train runs back and forth across the bridge.