While there have already been three movies in the DC Films Universe, also known as the DCEU (Expanded Universe), 2017 is when it will truly take shape. This year, we get out of the known cities of the DC Universe, and move into not just another set of locations in Themyscira and across Europe, but another era in World War I in Wonder Woman. Then later this year, the heroes of this world will band together, uniting as the Justice League. It's an exciting time for DC fans, who just a few years ago got another Superman reboot in Man of Steel and had no idea how much was on the way - but DC Entertainment and Warner Bros. knew, from the very start.

"When we started with Man of Steel, we knew that we were going to expand the universe," DC Films producer Charles Roven told ComicBook.com in an interview. "From the moment that we started with Man of Steel, we knew that once we opened up the Superman ... You can't do Superman without talking about aliens existing in our universe. We knew that we were going to have to really consider what the world building would be beyond the unique film. Then, as soon as Warner Brothers announced that slate, we really got intensive about it."

While they knew they were doing significant world building for the entire DC Universe with Man of Steel, they also knew early on that they were going to have many different takes on these characters - and that they wanted to do that. "But the thing is, each unique film in the DC pantheon is going to be unique because the directors are different except for Zack directing Man of Steel, Batman v Superman: Dawn of Justice, and the two Justice League movies. Each one of those directors, whether it be David Ayer or Patty Jenkins or James Wan, they are bringing their sensibilities and a different production designer and different costume designer, et cetera. That world building will still be of the same DC Justice League universe, but have its own unique point of view," Roven said.

They actually had meetings mapping out the "broad strokes" of the universe, building to Justice League and then exploring more of the individuals, but knew they wanted Wonder Woman before the team film to show her importance as "part of the trinity of DC Comics," Roven revealed. So, DC fans may want to go back and give Man of Steel another, deeper look. Just as it was made to tie directly into the story of Batman v Superman, with even some direct parallels shown in that second film, there might be clues throughout that lay the groundwork for the larger DCEU, from Wonder Woman to Justice League and beyond.