September 12, 2001 - Within 24 hours of the September 11 attacks, nations around the world, many of which had faced terrorist threats within their own borders, join against international terrorism. The U.N. General Assembly’s 191 nations condemn the September 11, 2001, attacks and, for the first time, America’s 18 NATO allies activate Article V of the founding treaty, which holds that an attack on any its member states will be considered an attack against them all. (© AP Images)