AIR STRIKES AND INVASION
October 7, 2001: The United States and Britain launch air strikes on Afghanistan after the Taliban refuse to hand over Osama bin Laden, who is held responsible for the September 11 attacks. Operation Enduring Freedom aims to hunt Bin Laden and topple the Taliban.
A broad military coalition includes the Afghan Northern Alliance, the United Kingdom and Canada.
November 13, 2001: After a lengthy U.S. bombing campaign against the Taliban, Northern Alliance fighters sweep in to Kabul on the backs of trucks and in cars. Taliban fighters flee to their strong stronghold in the south, Kandahar.
U.S. special forces and Northern Alliance fighters surround the Tora Bora caves in early December, but Osama bin Laden and Taliban leader Mullah Omar escape.
A NEW AFGHAN LEADERSHIP
December 7, 2001: Kandahar, the last area of Taliban control, falls to coalition forces. Hamid Karzi, a Pashtun from the south, emerges as leader. A draft constitution is negotiated in Bonn, Germany, and elections held in 2004. The largely peaceful elections result in Hamid Karzai being elected president.
Long seen as partner with Western nations contributing money and troops to the International Security Assistance Force, Hamid Karzai's tenure as president is clouded by allegations of corruption and declining public support.
January 2002: The United States begins to transfer terrorism suspects caught in Afghanistan to a naval base in Cuba. The Guantanamo facility sparks a major human rights debate and weakens America's standing in the Arab and Muslim world.
CANADA AT WAR
February 2, 2002: The first 25 Canadian troops arrive in Kandahar aboard a military transport plane. Canada will remain a key force contributor after NATO takes over control of the Afghanistan mission.
Kandahar province witnesses some of the fiercest fighting. By the time Canada's combat mission draws to an end in 2011, 157 Canadian soldiers are killed.
March, 2003: A U.S.-led invasion of Iraq to topple Saddam Hussein and eliminate his weapons of mass destruction. The war effort, and attempts to put down an Iraqi insurgency, stretches the US military as Iraq, not Afghanistan, becomes the focus.
Retired US Army Gen. Stanley McChrystal, who commanded coalition forces in Afghanistan from 2009-2010, said recently that the Bush administration's decision to invade Iraq hampered the Afghan mission because it diverted resources to Iraq from Afghanistan.
February 2007: In a brazen attack, Taliban fighters attack a U.S. base during a visit by U.S. vice president Dick Cheney. Twenty-four people are killed.
After being routed, the Taliban eventually regroup into an organized insurgency. The Taliban insurgency uses suicide bombers and improvised explosive devices throughout southern Afghanistan. Eventually, even northern Afghanistan, long seen as protected from Taliban activity, is no longer safe.
Western troop increases have little effect. "The Taliban fighters reservoir is practically limitless," the UN's Tom Koenigs tells Der Spiegel in 2006. "The movement will not be overcome by high casualty figures.
NEW AMERICAN POLICY
November 2008: Newly-elected US president Barack Obama pledges to pull US troops out of Iraq and focus on Afghanistan. After a lengthy review, President Obama orders a 30,000-troop surge that is to be followed by a US troops withdrawal.
March 22, 2011:Western military leaders begin handover of authority to Afghans, a process that will finish by 2014.
September 14, 2011: A 20-hour assault on the United States embassy in Kabul is put down. The U.S. blames the Pakistan-based Haqqani network for carrying out the attack and calls on Pakistan to reign-in the network. Increasingly, the problems in the Afghan mission are connected with Pakistan's unwillingness to crack down on terrorist safe havens.