The last day of the <a href="https://en.wikipedia.org/wiki/20th_century" id="mwAX8" rel="mw:WikiLink" title="20th century">20th Century</a> and <a href="https://en.wikipedia.org/wiki/2nd_millennium" id="mwAYA" rel="mw:WikiLink" title="2nd millennium">2nd Millennium</a>.