10 Movie Secrets Everyone Knows Except You
2. The "Keep Calm & Call Batman" Sign - Man Of Steel
Zack Snyder's Man of Steel is absolutely jam-packed with Easter eggs nodding to the wider DC Extended Universe, and particularly the existence of Batman himself, years before he showed up in earnest in Batman v Superman: Dawn of Justice.
Case in point, during the film's epically destructive climax, Superman (Henry Cavill) ends up inside a large skyscraper just as General Zod (Michael Shannon) uses his heat vision to rip it in half.
Keep an eye on the left-hand side of the frame, though, and you'll see a most bizarre poster. It's hard to make it out unless you're watching the 4K version of the movie, but it says "Keep calm and call Batman," with Batman's classic yellow-and-black logo at the top.
At the time of Man of Steel's release this was basically just an in-joke on the part of VFX company Double Negative, who previously worked on the Christopher Nolan Batman films.
But of course, Batman v Superman ended up not only introducing a veteran Batman (Ben Affleck) but also revealed that the very building Zod destroyed was the Wayne Enterprises HQ, in turn killing many of Bruce's own employees.
Though Snyder wasn't actively setting up the Batman-Superman conflict in Man of Steel, it's still a pretty neat secret in retrospect.