Ancient City Walls of Xian

I am reading about Ibn Batuta's voyage to China, which he considered the most sophisticated civilization of the time (despite their not being Muslims). Ibn Batuta was writing in the 14th century, during the reign of the last Khan before the descendants of Genghis Khan were overthrown by the Ming dynasty. Although I have not come across a mention of Xian, he does talk about a number of walled cities. I happened across this picture quite by chance, but it spoke to me.