A <a href="https://en.wikipedia.org/wiki/1139_Ganja_earthquake" id="mwHA" rel="mw:WikiLink" title="1139 Ganja earthquake">magnitude 7.7 earthquake</a> strikes the <a href="https://en.wikipedia.org/wiki/Caucasus" id="mwHQ" rel="mw:WikiLink" title="Caucasus">Caucasus</a> mountains in the <a href="https://en.wikipedia.org/wiki/Seljuk_Empire" id="mwHg" rel="mw:WikiLink" title="Seljuk Empire">Seljuk Empire</a>, causing mass destruction and killing up to 300,000 people.<sup about="#mwt15" class="mw-ref reference" data-mw='{"name":"ref","attrs":{"name":"Ulomov_&amp;_Medvedeva_2014"},"body":{"id":"mw-reference-text-cite_note-Ulomov_&amp;_Medvedeva_2014-1"}}' id="cite_ref-Ulomov_&amp;_Medvedeva_2014_1-0" rel="dc:references" typeof="mw:Extension/ref"><a href="./September_30#cite_note-Ulomov_&amp;_Medvedeva_2014-1" id="mwHw" style="counter-reset: mw-Ref 1;"><span class="mw-reflink-text" id="mwIA">[1]</span></a></sup>