WOW, it is surprising that you did not know this. That is the very beginning of the whole China-open-up-to-the-world story. Where were you in the last 4 decades?(teasing but no offense intended) P.S. Shenzhen began to change from the early 1980s.
However, it becomes less surprising to me of your past understanding/statement about China (being same same as old USSR) given your lack of information.
I wish you travel through China and her neighbors, such as Myanmar as you mentioned earlier, or other SE countries (besides Thailand frequented by westerns). You will probably be surprised.