grandeurgroup wrote:

Australia flag is one of the best flag in the world. Agree on guys?

No, it doesn't. It contains the 'Union Jack' (so, it isn't original at all) and also the Southern Cross constellation (on the right) is something not exclusive.
Flag of Australia:


Other flags with the Southern Cross constellation:
Christmas Islands


Cocos (Keeling) Islands


Brazil (in the centre)


New Zealand (more ancient than the flag of Australia)


Papua New Guinea


Samoa


Tokelau