No one is world famous
By its definition world fame is impossible, for anyone or anything.
There are whole groups of people who wouldnt know the US President, the Pope, Lady GaGa, the Mona Lisa, etc etc if they saw them.
That said:
What do we really mean by the term?
What's the minimum number of people knowing something/one needed to be considered world famous?
Is it just being known in certain parts of the world that can get something/one the status?
What parts of the world, if any, dont matter, to being world famous?