According to the recent cannon established by DC’s “New 52” reboot, during Batman’s early days as a hero Gotham City was taken over by the Riddler, who used stolen technology to completely control the city’s infrastructure systems. Not only that, but he used a stolen formula developed by the scientist Pamela Isley ,who would become the super-villain Poison Ivy, to transform the city into a jungle-like, post-apocalyptic wilderness. This period in the Gotham City’s history came to be known as “Zero Year”.
The transformation of Gotham City during Zero Year reminds me of a story from Alan Moore’s run on Swamp Thing (Swamp Thing no.53, 1986), during which Gotham City was transformed into an overgrown jungle. In “The Garden of Earthly Delights,” Gotham City has been taken over by trees, vines, plants, moss, and every other imaginable type of flora. The city was overrun by Swamp Thing, who was taking vengeance against the city for imprisoning his wife. Batman is called and attempts to meet with Swamp Thing, but is defeated in a brief battle.
Swamp Thing continues to escalate his attack, further strengthening his hold on the city, transforming it into a veritable Garden of Eden and some citizens of Gotham City begin to worship Swamp Thing. As Commissioner Gordon says, Swamp Thing gave Gotham “a taste of some sort of savage Eden. Some people out there are acting as if it’s a natural-born paradise…but all I can see is a green hell.”
The story also established, for the first time, the origin of Gotham City, which was founded by a Norwegian mercenary.