<a href="https://en.wikipedia.org/wiki/World_War_II" id="mwwg" rel="mw:WikiLink" title="World War II">World War II</a>: <a href="https://en.wikipedia.org/wiki/Allies_of_World_War_II" id="mwww" rel="mw:WikiLink" title="Allies of World War II">Allied</a> bombers conduct their most severe <a href="https://en.wikipedia.org/wiki/Bombing_of_Sofia_in_World_War_II" id="mwxA" rel="mw:WikiLink" title="Bombing of Sofia in World War II">bombing run</a> on <a href="https://en.wikipedia.org/wiki/Sofia" id="mwxQ" rel="mw:WikiLink" title="Sofia">Sofia</a>, <a href="https://en.wikipedia.org/wiki/Kingdom_of_Bulgaria" id="mwxg" rel="mw:WikiLink" title="Kingdom of Bulgaria">Bulgaria</a>.