If you are form Australia than no need to passport to travel < a href=http://www.cruiseeasy.com.au/>cruise Australia.
If you are a US citizen, you will need both a valid US passport and an Australian ETA visa to travel to Australia.
Yes, a US passport holder needs a visa to travel to Australia.
Yes
No, but you do need a valid passport.
Yes, a US passport holder can travel to Australia.
You'll need a US PASSPORT to return to the US.
Yes, anytime you leave the country you do.
Yes, you need a passport to travel to Europe.
Yes, you need a passport to travel to Paris.
No. You only need to use a passport if you are traveling overseas. This doesn't mean that it's free to travel from state to state.
You need a passport