Chusovaya River
... that a tributary of the Chusovaya River naturally dives underground for about 6 kilometres (3.7 mi)?
... that a tributary of the <b id="mwEgA"><a class="mw-redirect" href="./Chusovaya_River" id="mwEgE" rel="mw:WikiLink" title="Chusovaya River">Chusovaya River</a></b> <i id="mwEgI">(pictured)</i> naturally dives underground for about <span about="#mwt66" data-mw='{"parts":[{"template":{"target":{"wt":"convert","href":"./Template:Convert"},"params":{"1":{"wt":"6"},"2":{"wt":"km"}},"i":0}}]}' id="mwEgM" typeof="mw:Transclusion">6 kilometres (3.7</span><span about="#mwt66" typeof="mw:Entity"> </span><span about="#mwt66">mi)</span>?