April 11, 2016 is the starting date for production on Justice League: Part 1.
Due to several casting and production notices, the working title was revealed to be “Caveman”.
This is significant in that there’s a DC villain named Vandal Savage who was an immortal and has lived since the dawn of man, where he was a caveman granted strange powers by a fallen meteorite.
It’s likely that the title Caveman is a reference to Savage, and we will see him in the upcoming film.
Another interesting bit that was revealed is that one of the producers for the movie is George Miller, who almost made a Justice League film years ago until it was cancelled.
Justice League: Part 1 comes out November 17, 2017.