Buried Roman city (7)
I believe the answer is:
pompeii
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">buried roman city</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pompeii that I've seen before include "Site of an Italian disaster of AD79" , "City buried by volcanic eruption, AD 79" , "Roman site" , "Ancient city near Naples destroyed by volcano" , "Roman town buried by Vesuvius" .)