Famous waterfalls (7)
I believe the answer is:
niagara
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">famous waterfalls</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 niagara that I've seen before include "Famous waterfalls" , "US/Canadian falls" , "it's quite a height" , "Waterfall at Iran aga" , "Large water falls" .)