Holy city of Islam (5)
I believe the answer is:
mecca
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">holy city of islam</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for mecca that I've seen before include "Joint capital of Saudi Arabia" , "Holy city of Islam" , "Islamic holy city" , "Pilgrim's destination" , "place many visit" .)