There's digger corps, the capital is Canberra and our leader is John Curtin.
That's right: earlier this morning, 2K and Firaxis announced that Australia was being added as a playable faction. It's the next DLC pack for the game, but all users will also be getting a patch called the "Australian Summer" update "soon", which will add modding tools, multiplayer team functionality and Steam Workshop integration.
"Steam Workshop will allow you to browse, add, and subscribe to mods more easily, and the other tools will make it easier for artists and modders to express their creativity within the game," Firaxis said. "With the update to multiplayer you will be able to team up with your friends to conquer the world together against AI or human opponents."
As for the Australians, their unique improvement - no, really - is the "Outback Station":
Bit surprising Menzies wasn't chosen, given he was Australia's longest serving Prime Minister. In any case, we'll get to see how the Aussies stack up in Civilization "soon". Which could be a matter of days, a week, or more. (But probably about a week or so.)