<a href="https://en.wikipedia.org/wiki/World_War_II" id="mw4g" rel="mw:WikiLink" title="World War II">World War II</a>: The <a href="https://en.wikipedia.org/wiki/Soviet_invasion_of_Poland" id="mw4w" rel="mw:WikiLink" title="Soviet invasion of Poland">Soviet invasion of Poland</a> begins.