On this day in history - December 20

What Happened On This Day – December 20

• 2007 Queen Elizabeth becomes the longest-living British monarch

  The previous longest living monarch - Queen Victoria - died on Jan 22, 1901, when she was 81 years, 7 months, and 29 days old. Queen Elizabeth, who was born on 21 April 1926, turned 81 years, 7 months and 30 days on this day.

• 1999 Portuguese transfer sovereignty of Macau to China

  Portugal ruled over the special administrative region of China from the mid-16th century to 1999. Macau has a high degree of independence from China, and has control over its legal system, monetary system, and immigration policy.

• 1989 United States' invasion of Panama begins

  Also known as Operation Just Cause, the invasion took place under the leadership of President George H. W. Bush and led to the deposing of the dictator, Manuel Noriega. The invasion ended on January 31, 1990.

• 1973 Spanish Prime Minister Carrero Blanco assassinated

  A confidant of dictator Francisco Franco, Blanco was assassinated by the Basque nationalist and separatist group Euskadi Ta Askatasuna or ETA.

• 1803 Louisiana Purchase completed

  The United States was officially handed over the territory of Louisiana by the French. The French had regained control of the territory that spans over 15 present-day states and 2 Canadian territories in 1800. In 1762, Spain had taken over the territory.