TV and radio presenter Chris Tarrant journeys by rail through some of the world's most challenging terrain, beginning with a trip from Bangkok in Thailand to Mandalay in Myanmar. Chris traces the route of the notorious Burma-Siam Railway, a 250-mile long line built by the Japanese during World War Two using enslaved Asian workers and Allied Prisoners of War, visiting the famous site of the Bridge on the River Kwai along the way.

• Chris Tarrant