At more than 430 miles long, the Mauritania Railway has been transporting iron ore across the blistering heat of the Sahara Desert since 1963. One of the longest and heaviest trains in the world, the 1.8-mile beast runs from the mining center of Zouerat to the port city of Nouadhibou on Africa’s Atlantic coast. The train is the bedrock of the Mauritanian economy and a lifeline to the outside world for the people who live along its route. Video by Macgregor for National Geographic.