Stratego - Don't know if you were serious on the whole "Since when?" thing, but...
Canberra, the capital of Australia was named in 1913, and built over a site between Sydney and Melbourne, Australia's two largest cities (and Melbourne being the better of the two by far - it has REAL football). Australia's parliament started meeting there in 1927 (slow development - must have been due to the fact its surrounding territory lies in the state of New South Wales

). Between 1901 and 1927, Australia's parliament convened in Melbourne.
Regarding neighbours - We've only got 20 million or so people in a pretty large country, but much of it is desert. Most of our population lives on the eastern/south easter sea board in cities. Sydney has around 4.5 million, Melbourne 3.5 million (very rough - don't quote these figures. Someone correct me...). That being said, in the country and up north on cattle stations, there are vast distances between neighbours.
And yes there are Kangaroos, no they don't plague all our cities - possibly you could compare them to deer in the U.S. May appear in some outlying suburbs, but not an everyday sighting. Much more common in the country. And Canberra, which is more or less country. (350,000ish people)
Sorry this post was a little off topic...