The pictures on display at the Lanzhou Provincial Museum are very distinctive. What we are most familiar with is the "Yuanzhen Tu" portrait brick, which is the symbol of China Post. It was unearthed in the Wei and Jin tombs in 1972. The picture brick is a true portrayal of social life at that time, and the picture is the most complete of which is very vividly expressed in the postage situation in the northwest region more than a thousand years ago.