iron railing
... that pedestrians walking along Malet Street in London hear the sound of a stick hitting an iron railing ... though there's no railing in sight?
... that pedestrians walking along <a href="./Malet_Street" id="mwCdc" rel="mw:WikiLink" title="Malet Street">Malet Street</a> in <a href="./London" id="mwCdg" rel="mw:WikiLink" title="London">London</a> hear the sound of a stick hitting an <b id="mwCdk"><a href="./Iron_railing" id="mwCdo" rel="mw:WikiLink" title="Iron railing">iron railing</a></b><span id="mwCds" typeof="mw:Entity"> </span>... though there's no railing in sight?