After Zack Snyder released Man of Steel, reintroducing the world to a new, hairy-chested Superman, he went straight into the very ambitious Superman Vs. Batman project. And now Snyder has revealed how this idea evolved into something much larger than any of us anticipated.

In an interview with Forbes, Snyder spoke at length about his career (and it's a fun read, Snyder always gives an honest interview), but we were most interested in the Batman Vs. Superman reveals where Snyder reveals the thought process that turned the next Superman movie into a joint superhero project. It kind of makes sense.

When you came aboard Man of Steel, were you thinking in the back of your mind, "I could be the guy who gets to reboot Batman on film too!"

I gotta be honest, it definitely was a thing that… after Man of Steel finished and we started talking about what would be in the next movie, I started subtly mentioning that it would be cool if he faced Batman. In the first meeting, it was like, "Maybe Batman?" Maybe at the end of the second movie, some Kryptonite gets delivered to Bruce Wayne's house or something. Like in a cryptic way, that's the first time we see him. But then, once you say it out loud, right? You're in a story meeting talking about, like, who should [Superman] fight if he fought this giant alien threat Zod who was basically his equal physically, from his planet, fighting on our turf… You know, who to fight next? The problem is, once you say it out loud, then it's kind of hard to go back, right? Once you say, "What about Batman?" then you realize, "Okay, that's a cool idea. What else?" I mean, what do you say after that? …But I'm not gonna say at all that when I took the job to do Man of Steel that I did it in a subversive way to get to Batman. I really believe that only after contemplating who could face [Superman] did Batman come into the picture...

This year is the 75th anniversary of the first published Batman story, of course. But when the Man of Steel sequel hits theaters, it'll be the 75th anniversary of Wonder Woman's first appearance in comics as well. And this year happens to be the 40th anniversary of Wonder Woman's first live-action appearance, in the Cathy Lee Crosby TV movie on ABC. And on top of all of that, your "Man of Steel" sequel releases during the 35th anniversary of the first Christopher Reeve Superman film, too. So there's all of these anniversaries and all of this history coming together around this production. Had you realized how significant the timing of this film was going to be? And that you'd be launching the first movie really showing and firmly establishing the much bigger DC Universe on film at this important time in everyone's history?

We just went through Superman's 75th, and it was very exciting… and to me, it was just really awesome. And the idea of having the Batman 75th and the Wonder Woman 75th together is kind of an amazing thing, too… The thing also that's really fascinating for me is that, even just in the tests we've been doing, the costumes, right? You basically have Batman and Superman — and this is without Ben [Affleck] and Henry [Cavill] in the costumes, but just like the stand-ins, just testing to see what the costumes look like. And you have them standing there and they're standing in the same shot — and then we have Wonder Woman, you know, all three of them in the same shot. Even just for a test, you really have to go, "Wow, that's crazy!" Not only is it the first time that I'm seeing them, it's the first time they've ever existed together on screen in a movie. And that's kind of a huge deal. Even just Batman and Superman standing next to each other… [I]t's kind of epic. You do sort of sense the weight of the pop culture iconography jumping out of its skin when you're standing there looking at the two of them and Wonder Woman. It's crazy. But it's fun. I mean, I have the first photo, I've got it in my archive because I was like, "Okay, I better keep this, it's gonna be worth something," [laughs]!