Huge city (11)
I believe the answer is:
megalopolis
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">huge city</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for megalopolis that I've seen before include "city complex" , "Large conurbation" , "Group of large towns close together" , "Big city" .)