Loosely related, but two of my favourite quirks of historic international development / trade relating to China

https://en.m.wikipedia.org/wiki/Shanghai_International_Settl... The Americans/British and other European powers held and administered sovereign territory in Shanghai. Truly remarkable considering the historical implications.

https://en.m.wikipedia.org/wiki/Thirteen_Factories

Also the “factories” in Canton each administered by a foreign power or “Hong” (i.e. Jardine Mathieson (worth a google if you are unfamiliar), the portraits on the wiki link paint an otherworldy romantic picture of what was a remarkably profitable and wild trade…