Even Deborah Snyder appeared on camera. "That's how crazy it was!" she said.

Superman's funeral was easier to pull off - it was a procession with an unmarked casket wrapped in an American flag. "We were very unclear as to what it was," she explained. "People thought maybe the president died."

The shots of a candlelight vigil around Superman's new memorial - a simple seal with the words "If you seek his monument, look around you" - required a bit more sleight of hand: Cavill came to set to make it look like Clark Kent was covering the vigil as a journalist.

"I would tell [the extras] that there was a huge tragedy, and Superman saved the day," the director explained. "But there was a lot of emotion around what happened, and it's a sad day. Everyone worked it out in their own heads. There was one fireman who was really crying. I was like, Wow, that's great."