The Qinghai-Tibet railroad is the highest railroad in the world, climbing to more than 16,737 feet (5,072 meters). It connects Lhasa, Tibet, to the rest of China on 709 miles (1,142 kilometers) of track. Because of the high altitudes of the sections of the track, each rail car includes a supply of oxygen for its passengers. More than 1.5 million people used the train in its first year of operation in July 2006.