Sydney Observatory
...that from 1858 Sydneysiders could set their clocks by the ball dropped at 1 pm each day at the Sydney Observatory and that the observatory replaced Fort Philip which was never needed to be used for defending Sydney?
...that from 1858 <a class="mw-redirect" href="./Sydneysider" id="mwBfs" rel="mw:WikiLink" title="Sydneysider">Sydneysiders</a> could set their clocks by the <a href="./Time_ball" id="mwBfw" rel="mw:WikiLink" title="Time ball">ball</a> dropped at 1 pm each day at the  <b id="mwBf0"><a href="./Sydney_Observatory" id="mwBf4" rel="mw:WikiLink" title="Sydney Observatory">Sydney Observatory</a></b> and that the <a href="./Observatory" id="mwBf8" rel="mw:WikiLink" title="Observatory">observatory</a> replaced Fort Philip which was never needed to be used for defending <a href="./Sydney" id="mwBgA" rel="mw:WikiLink" title="Sydney">Sydney</a>?