The Tibetan Plateau forms the highest part of the country (the first step). Known as the 'roof of the world', the Tibetan-Qinghai Plateau is more than 5,000 feet above sea level. The Himalayan mountain range has a number of peaks over 23,000 feet, with the tallest in the world, Mount Everest, at the Sino-Nepalese border, Melting snows from these peaks are the source of several of the main Chinese rivers including the Yangtze and the Yellow River which run from west to east.