America's longest war has all but ended.

Launched in the wake of the September 11 attacks, the war in Afghanistan has claimed the lives of tens of thousands of Afghans along with around 2,400 US soldiers, and seen trillions of dollars squandered in what has largely been deemed a failed nation-building project.

Although the Taliban's hardline regime fell within a matter of weeks after the United States unleashed a ferocious bombing campaign and incited tribal uprisings, the conflict festered.

The initial celebratory images of men shaving their beards and women re-entering the workforce gave way to suicide bombings, mounting civilian casualties, and the resurrection of a Taliban movement hell-bent on ejecting foreign forces from Afghanistan.

What began as a mission to dismantle Al Qaeda's training camps in Afghanistan evolved over the years into a full-scale war against their Taliban hosts, triggering an insurgency that the US military's enormous firepower was unable to quell.

The killing of Al Qaeda leader Osama bin Laden in Pakistan in 2011 by US special forces renewed debate about the purpose of continuing the fight and eventually led to a failed effort to spur talks with the Taliban.

Former US president Donald Trump's election spelled the beginning of the end for the American involvement in Afghanistan, culminating in a landmark withdrawal deal hammered out between Washington and the Taliban's leadership in February 2020 in Qatar.

The final nail in the coffin came in April with his successor Joe Biden announcing that remaining US troops would be pulled from the country ahead of the 20th anniversary of the September 11 attacks, prompting America's Nato allies to follow suit.

But the US departure leaves Afghanistan facing an uncertain future, with an increasingly confident Taliban appearing to set the stage for a military takeover and another round of internecine civil war.

Header image: In this file photo taken on November 11, 2009, US Army soldiers from 2-506 Infantry 101st Airborne Division and Afghan National Army soldiers race to get out of the way of a CH-47 Chinook helicopter landing in hostile territory during the launch of Operation Radu Bark VI in the Spira mountains in Khost province, 5km from the Afghan-Pakistan border. — AFP