Event:
U.S. officials return four Afghan prisoners to Afghanistan after more than ten years of detention in Guantanamo Bay, Cuba; the Obama administration is working to clear and release remaining prisoners in order to close the facility
More Notable Events on December 20:
1993 Donald Trump weds Marla Maples
1989 U.S. troops invade Panama and oust Manuel Noriega, but don't catch him
1984 33 unknown Bach keyboard works found in Yale library
1963 Berlin Wall opens for 1st time to West Berliners
1920 Bob Hope became an American citizen