No self-respecting DC fan is unaware of the Batcave. And they might start seeing it — or what looks like the beginnings of what will later be the Batcave — in season two of "Gotham."

"Gotham" season one ended with a cliff-hanging scene, where the young Bruce Wayne (David Mazouz) and Alfred Pennyworth (Sean Pertwee) discover a secret passage leading to a bat-infested space, which looks very much like a cave. In the latest trailer, "Rise of the Villains," fans not only see more of Joker but also of this underground lair. So is this lair what every Batman fan knows as the Batcave?

Not quite so.

TV Insider posted a fresh photo of the bat-infested space but Mazouz warns, it is not to be called the Batcave. It will, however, definitely change young Bruce's life.

The young actor talks about what they discovered at the end of season one, "It changes everything in Bruce's life. It changes how he sees Alfred, the criminal side of Gotham, even how he sees his parents.... What is down there are clues to Thomas Wayne's secret life and what he was trying to do before being killed," he said.

So whether this secret underground space will hold Batman's future high-tech gadgets and toys or not remains to be unknown. But if there is one thing for certain, that is the Thomas Wayne secret that has been mentioned a lot and which Bruce tries so hard to uncover in season one, will surely matter a lot in the upcoming season.

Den of Geek also visited the "Gotham" set and took more photos of the not-Batcave. They noted that it does point to the early beginnings of Batman's secret hiding place. At the moment, though, it still is pretty much Thomas Wayne's space.

The photos showed a desk that housed the older Wayne's paperwork, files, and even family photos showing a baby Bruce. Thomas and wife, Martha, having been killed years prior to the show's timeline, contributed to the underground space having a lot of retro touches — from a magnifying glass to an old phone and computer monitor plus file cabinets reminiscent of old offices.

In a separate interview with Mazouz by Den of Geek, he echoed what he already said about the Batcave predecessor, "That discovery, what he finds at the bottom of those stairs, it's going to change the course of his whole life entirely and every aspect of his life, along with it. It's going to change his relationship with Alfred, the way he sees Alfred, the way he sees his parents, the way he sees himself, really, because he identified with his parents. And he's gonna learn a lot about his dad. He's gonna learn a lot about Wayne Enterprises. And it will bring him a lot closer to finding out who killed his parents."

"Gotham" season two premieres on Fox this Sept. 21.