A timeline of the US withdrawal and Taliban recapture of Afghanistan

WASHINGTON — Nearly two decades after the U.S. invaded Afghanistan, the nation's capital fell back under Taliban control.

And just weeks ahead of the planned pullout of American troops, the American flag at the U.S. embassy in Kabul had been taken down and most embassy staff had been relocated to the city's airport.

The chaotic reports emerging from Kabul cap more than two decades of American efforts in the country to root out terrorism and transform the nation into a functioning democratic state. Thousands of American lives and nearly $830 billion in official spending, those efforts have resulted in failure.

How Afghanistan, a country that has been torn by conflict for decades, arrived at this place is a long and arduous journey.

More: After two decades and billions spent, Afghan government collapses as Taliban takes Kabul

See for yourself: Visual story: Kabul's airport chaos and the Taliban advance, explained with maps and graphics

Here is a timeline of Afghanistan's more late 20th century, what led to the U.S. invasion in the first place, through the most recent action there:

April 1979: In the Saur Revolution, or April Coup, the People's Democratic Party of Afghanistan assassinates Afghan President Mohammed Daoud Khan.

December 1979: Soviets invaded Afghanistan in order to prop up the government, which faced internal rebellion.

Early 1989: As the Soviet Union disintegrated, the army withdrew, leaving the Afghan forces to take the lead in fighting an American-funded insurgency. US intelligence estimates over 15,000 Soviet troops died in the decade-long war. The Soviets kept advisers with the Afghans and continued financing the military.

1992: The American CIA, which backed Afghan rebel groups, withdrew its aid. The Russians also cut its funding. The pro-Russian government was overthrown, and Afghanistan was plunged into a bloody civil war, setting the stage for the Taliban to assume power four years later.

1994: The Taliban, or "students" in the Pashto language, emerges from Islamist fighters in Pakistan and Afghanistan who fought against the Soviet invasion of Afghanistan for over a decade. That conflict ended in 1989.

1996: After a two-year civil war, most of Afghanistan comes under the control of the Taliban, who institute fundamentalist policies and widespread repression of human rights.

Sep.11, 2001: Terrorists affiliated with al-Qaida hijack commercial planes to execute terror attacks on the World Trade Center in New York City and the Pentagon outside Washington. The terrorists planned, trained and directed the attacks from Afghanistan.

Oct. 7, 2001: U.S. and United Kingdom forces begin Operation Enduring Freedom, a bombing campaign against Taliban forces in Afghanistan.

Dec. 17, 2001: U.S. and allied forces have driven Taliban from power in Afghanistan. Al-Qaida disperses.

April 17, 2002: President George W. Bush calls for a Marshall Plan for Afghanistan.

March 20, 2003: U.S. invades Iraq, diverting military resources and attention from Afghanistan.

Feb. 17, 2009: President Barack Obama recommits U.S. forces to Afghanistan to combat "resurgent" Taliban.

March 27, 2009: Obama announces new strategy for Afghanistan, connecting the return of the group in parts of the country to the Pakistani Taliban. He calls for greater cooperation from Pakistan.

Dec. 1, 2009: Obama announces 30,000 additional troops will be sent to Afghanistan on top of the 68,000 already stationed in the country in a move later known as "the surge."

May 2, 2011: Obama announces the U.S. military and CIA agents successfully found and killed Osama bin Laden.

June 22, 2011: Obama announces troop draw downs to begin in Afghanistan.

Dec. 5, 2011: World leaders gather in Bonn, Germany, to discuss how to build a road map for the future of Afghanistan. U.S. and Western allies commit billions in investment to support development of Afghan government.

May 27, 2014: Obama announces plan for full troop withdrawal from Afghanistan by end of 2016.

Sep. 4, 2014: NATO issues a joint statement, designating that Afghan Security Forces "will assume full responsibility for security" of the country by the end of the year. International coalition ends its operations in Afghanistan, U.S. continues its own battle.

Aug. 21, 2017: President Donald Trump cautions against "hasty" troop withdrawal from Afghanistan that "would create a vacuum." Trump said that he shares Americans' "frustration" with foreign wars, assures that "we are not nation-building again; we are killing terrorists."

Sep. 7, 2019: Trump calls off U.S.-Taliban peace talks that began in late 2018.

Feb 29, 2020: President Donald Trump negotiates a deal with the Taliban for U.S. troop withdrawal by May 1, 2021.

Nov. 17, 2020: Pentagon announces plans to reduce troop levels to 2,500 in Afghanistan and Iraq in final days of Trump administration.

New commander-in-chief: Trump claims Afghanistan withdrawal would have been 'much more successful' if he were president. Would it?

April 14, 2021: President Joe Biden announces that full troop withdrawal from Afghanistan will be complete by Sept. 11.

May 1: The U.S. begins final troop withdrawal from Afghanistan.

July 6: The U.S. evacuates Bagram Airfield, the largest military installation in the country since 2001 invasion.

Aug. 6: Provincial capitals begin to fall to the Taliban.

Aug. 8: Provincial capitals Sar-e-Pul, Kunduz and Taloqan all fall to the Taliban.

Aug. 11: Fall of provincial capitals of Badakhshan and Baghlan provinces to the northeast and Farah province to the west.

Who are the Taliban? Many fear Taliban will again end Afghan human rights, support terrorism

Aug. 13: The county's second-largest city, Kandahar, a cultural center and the foundation site of the Taliban, falls to the fundamentalist group.

Aug. 14: The country's fourth-largest city, Mazar-e-Sharif, falls to the Taliban.

Aug. 15: Kabul, the national capital, falls to the Taliban. Afghan president flees country, government collapses. U.S. Embassy in Kabul is evacuated.

Aug. 26: Amid evacuations of Americans and U.S. allies, ISIS-K sets off two suicide bombs outside Kabul airport, killing at least 13 U.S. service members and scores of Afghans.

More: Taliban's Afghanistan advance tests Biden's 'America is back' foreign policy promise

Follow Matthew Brown online @mrbrownsir.

This article originally appeared on USA TODAY: A timeline of Afghanistan's history and US involvement