Burj Khalifa's city (5)
I believe the answer is:
dubai
'burj khalifa's city' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dubai that I've seen before include "Port city of UAE" , "Persian Gulf state" , "Port city on the Persian Gulf" , "Gulf emirate and port city" , "Arab city" .)