TWO DECADES AT WAR: THE UNITED STATES IN AFGHANISTAN

JAN. 28, 2019: Taliban and U.S. officials meeting in Qatar agree to begin intensive negotiations to resolve the conflict in Afghanistan. The talks don’t involve the Afghan government, which the Taliban refuses to recognize. FEB. 29, 2020: The Trump administration and the Taliban reach an agreement to withdraw U.S. troops from Afghanistan by May 1, 2021. As part of the deal, the Taliban agrees to cut ties with al-Qaida and refrain from attacking U.S. forces. In return, the U.S. pressures the Afghan government to release 5,000 Taliban prisoners. APRIL 14, 2021: President Joe Biden pushes back the deadline for pulling out U.S. troops until Sept. 11, but he says he’s committed to ending the war. JULY 6: U.S. forces abandon Bagram air base, its largest military facility in Afghanistan. Two days later, Biden says “speed is safety” when it comes to pulling out troops, and the withdrawal will be finished Aug. 31. AUG. 15: After toppling a series of provincial capitals, the Taliban sweep into Kabul and take control of the city. With just two weeks until the deadline for withdrawing, U.S. officials begin organizing a massive evacuation for Americans and Afghan allies.

AUG. 26: Islamic State terrorists, who are hostile to both the Taliban and the United States, attack the evacuation operation. Thirteen U.S. service members and nearly 200 Afghans are killed. Biden vows retaliation, and U.S. forces launch drone strikes against the Islamic State affiliate.

AUG. 31: The final U.S. troops depart the night before the deadline for the withdrawal.

VICTOR J. BLUE/NEW YORK TIMES Taliban fighters last month secure helicopters disabled and left by U.S. forces in Kabul.

RAHMAT GUL/ASSOCIATED PRESS 2021 Afghan men sit in the sun on a cold day last January in Kabul, Afghanistan.

RAHMAT GUL/AP 2021 Afghan soldiers patrol outside their military base in May on the outskirts of Kabul, Afghanistan.