you must Dunhuang Mogao...
you must Dunhuang Mogao Grottos, you will watch many wonderful mural which were paited in Tang Dynesty.
you must go to Dunhuang Desert,it is Chinese Sahara.
You must go to see Yellow River, it is the place of Origin of Chinses culture Walk on the Dunhuang Desert, see the sun rising in the morning in the desert.
Lanzhou Lamien and other great things
"Go to Lanzhou!"
Lanzhou is a decent city by itself. Considering how far out in the middle of nowhere it is, it has all the basic facilities of a big city. The people are nice and the food is good. One of Lanzhou's drawbacks is it is the industrial and governmental center for this part of China. It is dirty and dusty and is considered by many, the most polluted city in China. However, in Gansu, this might be the only polluted place. Much of Gansu is pristine and natural. Most of the people just barely get by trying to farm in the desert, semi-desert, or the mountains. The culture here is amazing. There are many Chinese minorities and a huge Muslim population. In the western part of Gansu, just a few hours from Lanzhou, you will even find Labrang Monastary, a huge religious town full of friendly people, surrounded by gorgeous scenery. Visit lanzhou and the rest of Gansu! Its great.