Under normal operation, our North American user (left) will connect to region A, which, for practical reasons, we've deployed in us-east-1, although it could be in any region. Our Australian user (right) will connect to region B, which is the region we've designated as being for the rest of the world. Again, for practical reasons, we deployed this site to the ap-southeast-2 region:
Left: Region A served to North American user. Right: Region B served to Australian user.