1240: Mongols led by Batu Khan occupy and destroy Kyiv after an 8 day siege; out of 50,000 people in the city only 2,000 survive

1865: 13th Amendment of the United States Constitution is ratified, abolishing slavery (except as a punishment for crime whereof the party shall have been duly convicted,)

1921: Anglo-Irish Treaty signed; Ireland receives dominion status; partition creates Northern Ireland

1998: Hugo Chávez is elected President of Venezuela

2006: NASA reveals photographs taken by Mars Global Surveyor suggesting the presence of liquid water on Mars

Source: Onthisday.com