The director Luc Besson (Fifth Element) is using Instagram to document every step of making his next film, Valerian.
Besson's Instagrams show storyboards, costumes, blue-screen action, and more.
You can take a look here: https://www.instagram.com/lucbesson/
If you click on the individual images you'll see a title or description by Besson and comments from visitors to the site. As of this writing, he's on day 87.