The reign of the Qianlong Emperor
There’s an interesting book by a couple of architectural engineers, Salvatore and Levy, called Why Buildings Fall Down. In the introduction, one of them recounts giving a copy of his previous book, Why Buildings Stand, to his aunt. She read it. When he asked her how she liked it, she said that it was good, but that much more interesting would be the converse: why they fail. He was crestfallen, but took it to heart. The subsequent book is wonderful.
OK, so the emperor was the Asian counterpart to the Sun King. The Central Kingdom runs like a Swiss watch. Well and good. What went wrong?