Afghanistan, a Central Asian nation of deserts, mountains, and scrubland bridging the Middle East to Asia, has had a turbulent history -- the latest chapter of which began with the U.S. and British bombing following the September 11, 2001 attacks in the U.S.. Several ethnic groups live in Afghanistan, with the Pashtun and the Tajiks being the largest two. As a country, Afghanistan is the largest source of refugees: 3.5 million. Subjected to invasions since at least the time of Alexander the Great, Afghanistan's most recent invasion prior to the bombing was by the Soviet Union, from 1979 to 1989. Following the Soviet Union's withdrawal, interethnic and political rivalries kept the country at war until the Taliban militia, with strong support from Pakistan, established relative peace in 1996 and began a program of turning Afghanistan into a fundamentalist regime. Alienating every neighbor but Pakistan, it was soon only officially recognized by Saudi Arabia and the United Arab Emirates.