Dunhuang Mogao Grottoes is one of the most famous place of interest in Gansu province and most important site for the silk road. There are thousands of caves there. It's kind of depository of historical and cultural exchanges of china and other nations.

If you want to enjoy the unique Loess Plateau in Gansu, this is one of the most appealing place. It's about 1100km from the capital city, Lanzhou.