Conversation so far:
when did they film season 2 of stranger things
Stranger Things 2 filming was underway from November 2016 through June 2017.
when did the second season of stranger things come out on netflix
Stranger Things 2, was released worldwide exclusively via Netflix's web streaming service on October 27, 2017.

Question: who created the series
Self-contained rewrite: who created the series stranger things