The bridge of the River Kwai was originally built by the labor of Allied prisoners of war. Under the control of the Japanese army Construction took only one year to complete. Before it was bombed and destroyed by the Allied air force until the middle of the bridge collapsed. Later, after the world war ended The Thai government purchased this railway from England. After this, a 2-span steel bridge was built in place of the original, and the wooden bridge section at the end was changed to a steel bridge instead.