City on the Rhine (5)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">city on the rhine</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 basel that I've seen before include "In European city" , "City of Switzerland" , "Swiss city" .)
(Another definition for mainz that I've seen is " port in Germany".)
(Other definitions for arnhem that I've seen before include "Location of battle" , "Second World War battle" , "Dutch city" , "Netherlands scene of 1944 battle" , "place noted for fighting" .)