However, the "uninhabited" part proved to be a bit of a dud: There were plenty of natives wandering the area wondering what the hell Batman was doing there. Being a nice guy, he didn't just kick their asses and take the land by force. Instead, he became one of the few Australian settlers to actually pay for the land he used. This was a good deal from the Aborigines' point of view, as they had never really conceived of owning the land in the first place. It was a great deal for Batman, who, according to his own words, was now "the greatest landowner in the world." This treaty became known as Batman's Deed, because sometimes the universe just gets things goddamn right.
Now free to establish the city of his dreams, Batman brought in a bunch of settlers, set up shop, and named the place Gotham City. Ha, just kidding! He decided to take the "8-year-old naming his tree house" route and dubbed the city Batmania.
His entire Rogues Gallery was spider-themed.
Despite sounding like a combination of an Adam West wrestling show and the aftermath of a rabid bat attack, Batmania was off to a good start. However, a rival land plotter called Richard Bourke soon saw that Batman was on to a good thing and decided to swoop in, presumably in full Joker makeup. With the backing of the government, Bourke ripped up the treaty and started taking over the city. Batman did not like it one bit, but since the city was becoming the regional capital and Bourke happened to be the governor of said region, the Australian government put its foot down and basically told Batman (and the Aborigines) to eat a great big bag of platypus dicks.