Looking at those pictures, I now know why my FIL, a structural engineer, is always complaning about high steel and cement prices.
About all I could tell you about the city is that it exists (I know it as Chungking, BTW) and there’s a place called Chungking Mansions in Hong Kong.
I’ve travelled a fair bit myself (not to China, admittedly), but one of my friends from uni spent a year in China teaching English and said he ended up in a Chinese city which had a population larger than Adelaide (ie over 1 million people) yet was considered (by Chinese standards) to be an insignificant semi-rural town.
According to Wiki, there are 160+ cities with population over 1 million in China based in administrative area. You could think of the administrative area as something like San Francisco versus the Bay Area or LA versus the Greater LA metropolitan area
Based on the urban area, which is what most people would probably call the city area, Chongqing is about #15.
For several years I worked for a guy who was born in Chongqing. But he had left for Taiwan as a small child, when the Commies took over.
I don’t know anything about it other than that it is surprisingly far inland for such a huge city.