This is pretty awesome. Back in the day, before CGI and green screen ran the movie business, you had to do things a little more old fashion. You had to literally PAINT the backgrounds of your movie world with incredibly detail-oriented techniques, and film them in such a way that they would be seen like a realistic and life-like backdrop. Here's a look at some of the paintings for Empire Strikes Back and Return Of The Jedi by Ralph Mcquarrie, Michale Pangrazio, and Chris Evans.