The <a href="https://en.wikipedia.org/wiki/Soviet_Union" id="mwmQ" rel="mw:WikiLink" title="Soviet Union">Soviet Union</a> begins mass deportations of Polish citizens from <a href="https://en.wikipedia.org/wiki/Territories_of_Poland_annexed_by_the_Soviet_Union" id="mwmg" rel="mw:WikiLink" title="Territories of Poland annexed by the Soviet Union">occupied eastern Poland</a> to Siberia.