E04: The fourth episode looks at the lands north of Chinaâ€™s Great Wall. Here, nomadic tribes from a variety of ethnic groups still roam, but their traditional ways of life are changing as people move to modern cities. In ancient Manchuria, the last Hezhe fishermen still cast their nets beneath the thick ice of the frozen Black Dragon River. The forests here support wild boar, which forage for walnuts in winter, and the last remaining wild Siberian tigers in China. Ewenki reindeer herders came from Siberia hundreds of years ago: now, only 30 remain. Further west lie the rolling Mongolian steppe grasslands, and at Bayan Bulak, the livestock of Mongolian horsemen share the pastures and wetlands with breeding demoiselle cranes and whooper swans. Continuing westwards, the land becomes increasingly hot and dry, turning first to arid grasslands roamed by rare goitered gazelles, and then to the Taklamakan Desert, the worldâ€™s largest shifting sand desert. Here stand ruined towns, a legacy of the Silk Road, and many yardangs, sand-sculpted rock formations. Underground irrigation canals at the Turpan oasis enable grapes to be cultivated, and red-tailed gerbils are quick to take advantage. Kazakh nomads spend the summer in the Tian Shan before descending to the Junggar Basin, an arid land bordering the Gobi Desert, to overwinter. Here their livestock shares the meagre pasture with the last wild horses on earth. A Kazakh demonstrates the 6000-year-old tradition of hunting with golden eagles. The closing scenes show the Harbin Ice Festival.