Nereus
... that on May 31, 2009, the ROV Nereus reached an underwater depth of 10,902 metres (6.8 mi), becoming the world's deepest-diving vehicle?
... that on May 31, 2009, the <a href="./Remotely_operated_underwater_vehicle" id="mwC1k" rel="mw:WikiLink" title="Remotely operated underwater vehicle">ROV</a> <i id="mwC1o"><b id="mwC1s"><a href="./Nereus_(underwater_vehicle)" id="mwC1w" rel="mw:WikiLink" title="Nereus (underwater vehicle)">Nereus</a></b></i> reached an underwater depth of <span about="#mwt31" data-mw='{"parts":[{"template":{"target":{"wt":"convert","href":"./Template:Convert"},"params":{"1":{"wt":"10902"},"2":{"wt":"m"},"3":{"wt":"mi"},"4":{"wt":"1"}},"i":0}}]}' id="mwC10" typeof="mw:Transclusion">10,902 metres (6.8</span><span about="#mwt31" typeof="mw:Entity"> </span><span about="#mwt31">mi)</span>, becoming the world's deepest-diving vehicle?