Top of the world (5,4)
I believe the answer is:
north pole
'top of the world' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for north pole that I've seen before include "Extreme Arctic position" , "Where the only way is down" , "One end of earth's axis" , "Arctic goal" , "Hotel porn (anag)" .)