Yadan, meaning Steep Mounds in Uygur, now refers to the special topography alike in dry region. The clayish rock became a series of ditches and ridges in the direction of the prevailing wind as an effect of strong water corrosion and wind erosion. Those marvelously shaped ditches and ridges, usually extending dozens meters long, even hundreds, forms a spectacular view in Lop Nur, which has Yadan topography to its east, west and north. Among them, Yadan in the east, called Dragon City, is the most thrilling one, which occupies 3500 square meters.