Film: Raiders of the Lost Ark (1981)
What: R2-D2 and C-3P0 make a cameo
Two installments of Star Wars had already been released — Episode IV: A New Hope (1977) and Episode V: The Empire Strikes Back (1980). And if you’ve noticed how people are popping wood for J.J. Abrams upcoming Episode VII: The Force Awakens, you know how wildly popular the Star Wars films are. However, Lucas also had a hand in the original Indiana Jones film series, getting credit as co-creator and writer of Raiders, Temple of Doom (1984), and The Last Crusade (1989). A small connection between the franchises can be seen in Raiders when Indy is rummaging through the Temple of Akator. You can see it more clearly here:
