obelisk
...that the obelisk in Rome's Piazza Montecitorio was erected in 10 BC as a giant sundial gnomon, but stopped keeping accurate time within 30 years?
...that the <b id="mwDqE"><a href="./Obelisk_of_Montecitorio" id="mwDqI" rel="mw:WikiLink" title="Obelisk of Montecitorio">obelisk</a></b> in <a href="./Rome" id="mwDqM" rel="mw:WikiLink" title="Rome">Rome</a>'s <a href="./Piazza_di_Monte_Citorio" id="mwDqQ" rel="mw:WikiLink" title="Piazza di Monte Citorio">Piazza Montecitorio</a> (<i id="mwDqU">pictured</i>) was erected in <a href="./10_BC" id="mwDqY" rel="mw:WikiLink" title="10 BC">10<span id="mwDqc" typeof="mw:Entity"> </span>BC</a> as a giant <a href="./Sundial" id="mwDqg" rel="mw:WikiLink" title="Sundial">sundial</a> <a href="./Gnomon" id="mwDqk" rel="mw:WikiLink" title="Gnomon">gnomon</a>, but stopped keeping accurate time within 30<span id="mwDqo" typeof="mw:Entity"> </span>years?