Gilgel Gibe II Power Station
... that shortly after its inauguration, part of the Gilgel Gibe II Power Station's 26 km (16 mi) tunnel, which was "considered one of the most difficult tunnel projects ever undertaken", collapsed?
... that shortly after its inauguration, part of the <b id="mwGf0"><a href="./Gilgel_Gibe_II_Power_Station" id="mwGf4" rel="mw:WikiLink" title="Gilgel Gibe II Power Station">Gilgel Gibe II Power Station</a></b><span about="#mwt92" class="nowrap" data-mw='{"parts":[{"template":{"target":{"wt":"`s","href":"./Template:`s"},"params":{},"i":0}}]}' id="mwGf8" typeof="mw:Transclusion"><span typeof="mw:Entity">'</span>s</span> <span about="#mwt93" data-mw='{"parts":[{"template":{"target":{"wt":"Convert","href":"./Template:Convert"},"params":{"1":{"wt":"26"},"2":{"wt":"km"},"3":{"wt":"mi"},"abbr":{"wt":"on"}},"i":0}}]}' id="mwGgA" typeof="mw:Transclusion">26</span><span about="#mwt93" typeof="mw:Entity"> </span><span about="#mwt93">km (16</span><span about="#mwt93" typeof="mw:Entity"> </span><span about="#mwt93">mi)</span> tunnel, which was "considered one of the most difficult tunnel projects ever undertaken", collapsed?