On this day — December 22

federal government in history, begins.

making it the first proven vaccine against the disease.

don't tell policy, the 17-year-old policy banning homosexuals serving openly in the United States military, is signed into law by President Barack Obama.

political leader of the Northern Alliance, hands over power in Islamic State of Afghanistan to the interim government headed by President Hamid Karzai.

Korean Air Cargo Flight 8509 crashes into Hatfield Forest near Great Hallingbury, killing all four people on board.

Attendees at a prayer meeting of Roman Catholic activists for indigenous causes in the small village of Acteal in the Mexican state of Chiapas are massacred by paramilitary forces.

Hussein Farrah Aidid relinquishes the disputed title of President of Somalia by signing the Cairo Declaration, in Cairo, Egypt. It is the first major step towards reconciliation in Somalia since 1991.

Virginia, killing all six people on board.

a Boeing 727 operating as Libyan Arab Airlines Flight 1103 collides in mid-air with a Libyan Air Force Mikoyan-Gurevich MiG-23, killing 157 people.