The Longest Train in the World runs through the Sahara Desert in Mauritania from Nouadhibou to Choum . It transports iron-ore from Zouerat to Nouadhibou and is 2.5km long. It is a 460km/12hrs journey. There many bucket wagons for the ore, which also accomodates passengers who may travel for free but must endure extremes of heat and cold, sand and dust from the iron ore. There is also just one passenger wagon.