Warning: Graphic images

Soon after the attacks of September 11, 2001, the US military's attention turned to Afghanistan, where al-Qaida's leaders were based. Many knew an invasion was sure to come.

What no one knew was that Operation Enduring Freedom, the invasion to rout al-Qaida and its hosts, the Taliban, would turn into a war that is now in its 19th year — America's longest.

It has vexed three American presidencies and outlasted 13 US military commanders. It has also opened a window, for much of the world, onto a country where modernity still clashes with ancient customs and religious edicts.

Here, in chronological order, are images showing the long arc of the war, as seen through the eyes of New York Times photographers.

2001-2002: The war begins

Operation Enduring Freedom began on October 7, 2001, with an American bombing campaign against al-Qaida and the Taliban. On the ground, US Special Operations forces teams linked up with Afghan militias opposed to the Taliban, mainly the Northern Alliance, to drive the Taliban from power. The capital, Kabul, fell in mid-November, along with the Taliban stronghold of Kandahar.

In December, Osama bin Laden, al-Qaida's leader, escaped to Pakistan through the mountains around Tora Bora. That same month, an interim Afghan government led by Hamid Karzai was installed.

A United Nations Security Council resolution established the International Security Assistance Force, or ISAF, a military coalition led by the United States.

An American B-52 bomber circled above Tora Bora in eastern Afghanistan, December 2001. Photo / Joao Silva, The New York Times

American soldiers at Bagram Air Base, north of Kabul, in August 2002. Photo / Tyler Hicks, The New York Times

On their way into Kabul, Afghanistan, in November 2001, Northern Alliance members found a Taliban fighter in a ditch and killed him, despite his pleas. Photo / Tyler Hicks, The New York Times

2003-2007: Drift to Iraq

Defence Secretary Donald Rumsfeld announced an end to major combat operations in Afghanistan in May 2003. Even with a major reconstruction effort underway there, and about 8,000 US troops in place, President George W. Bush's administration began shifting combat resources to the war in Iraq.

In 2004, an Afghan assembly drafted a Constitution. Zalmay Khalilzad, then the American ambassador, said it contained "the foundation for democratic institutions."

The Taliban-led insurgency grew stronger in 2006, carrying out more ambushes and suicide bombings. Despite training and equipment supplied by the United States and ISAF, Afghan security forces could not contain the Taliban resurgence, aided by militants across the border in Pakistan. The United States sent more of its soldiers to the war.

By 2007, about 25,000 US troops were in Afghanistan.

The shadow of a US soldier on patrol in Afghanistan's Paktika Province, near the border with Pakistan, in August 2005. Photo / Scott Eells, The New York Times

American soldiers yelled to others to get out of the line of fire after being ambushed by Taliban fighters in southern Afghanistan, in June 2006. Photo / Tyler Hicks, The New York Times

Wounded soldiers in the Korengal Valley in eastern Afghanistan, in October 2007. Photo / Lynsey Addario for The New York Times

2008-2010: Recommitment and surge

In February 2009, the new American president, Barack Obama, declared a recommitment to the war and deployed 17,000 more troops to Afghanistan, adding to the 36,000 already there.

In December, Obama announced a "surge" meant to build and train an Afghan security force that would be strong enough to assume responsibility for fighting the insurgency. His plan included sending 30,000 more US troops, bringing the total number to nearly 100,000 by mid-2010.

President George W. Bush with President Hamid Karzai of Afghanistan during a visit to Kabul, in December 2008. Photo / Lynsey Addario, The New York Times

Soldiers from the First Infantry Division on a foot patrol in Hutal, in the southern province of Kandahar, Afghanistan, in January 2009. Photo / Danfung Dennis, The New York Times

A bullet-pierced window at a Kabul guest house attacked by the Taliban, in November 2009. Five United Nations workers were killed. Photo / Moises Saman, The New York Times

A suicide bomber struck near a hotel in Kabul in December 2009, killing at least eight people and wounding dozens. Photo / Adam Ferguson, The New York Times

Village elders meeting in Marja, in March 2010. Photo / Moises Saman, The New York Times

Afghan soldiers rushed a wounded police officer to an American helicopter in Kunar Province, Afghanistan, in March 2010. Photo / Moises Saman, The New York Times

American soldiers on a transport plane about to land in Mazar-i-Sharif, Afghanistan, in April 2010. Photo / Damon Winter, The New York Times

An American soldier looking over the Pech Valley, in Kunar Province, Afghanistan, in April 2010. Photo / Christoph Bangert, The New York Times

2011-2013: A troop drawdown

In May 2011, a US Navy SEAL team killed Osama bin Laden in a compound in Abbottabad, Pakistan, where he had been living for years. In June, Obama announced that he would pull 33,000 troops from Afghanistan by mid-2012.

In 2012, Afghanistan's president, Hamid Karzai, began blaming United States and coalition troops for rising civilian casualties, as his relationships with American leaders deteriorated.

Afghans took over most security responsibilities in 2013, with the US-led coalition's forces shifting to training and counterterrorism operations.

Soldiers boarded a transport helicopter in Kunduz, in March 2011. Photo / Damon Winter, The New York Times

Afghan soldiers, left, and American soldiers blew up a Taliban firing position in the village of Layadira, in Kandahar Province, in February 2013. Photo / Bryan Denton, The New York Times

Samiullah, 8 months old and malnourished, is held by his mother, Islam Bibi, 15, at a hospital in Lashgar Gar, in Helmand Province, in September 2013. Photo / Daniel Berehulak, The New York Times

Sayed Wazir, 40, a former mujahadeen, firing a rocket toward Taliban positions in surrounding hills, in Wardak Province, in November 2013. Photo / Daniel Berehulak, The New York Times

2014-2018: A Taliban resurgence

On December 31, 2014, the combat mission in Afghanistan formally ended, but the US military presence in the country did not. Obama announced a timetable for the withdrawal of most troops by the end of 2016.

After a 2014 election marred by fraud, Ashraf Ghani became president, but he signed a power-sharing agreement with his top opponent, Abdullah Abdullah.

On the battlefield, the Afghan security forces increasingly struggled against the Taliban taking heavy casualties and losing territory.

In August 2017, President Donald Trump said that while his first instinct had been to withdraw all troops from Afghanistan, he would continue to prosecute the war. He stressed that withdrawal decisions would be based on combat conditions, not on predetermined timelines.

The United Nations said 2018 was the deadliest year for Afghan civilians since it had begun tracking civilian casualties 10 years earlier.

The aftermath of an American airstrike on the Doctors Without Borders hospital in Kunduz, in October 2015. Forty-two people were killed in the attack. Photo / Victor J. Blue, The New York Times

The outskirts of Khost, a city in eastern Afghanistan, in July 2018. Photo / Jim Huylebroek, The New York Times

2018-2020: Peace talks and a historic deal

Late in 2018, American and Taliban negotiators began holding peace talks. The discussions continued well into 2020, in Doha, Qatar. (The Afghan government was excluded from the talks — the Taliban refused to meet with its officials.)

On February 29, the United States signed a peace deal with the Taliban, opening the door to a gradual, final troop withdrawal from Afghanistan, and the beginning of direct talks between the Afghan government and the insurgency to determine the country's future.

As of February, about 12,000 US troops were still in the country.

The United States has spent more than US$2 trillion on the war effort. More than 2,400 U.S. troops and nearly 700 troops from other nations in the coalition have died. More than 38,000 civilians have been killed, and among the Afghan security forces, about 60,000 are estimated to have died since the start of the war.

Written by: Rod Nordland and David Zucchino
Photographs by: New York Times
© 2020 THE NEW YORK TIMES