Short answers, pulled from the story.
The chancery on Great Massoud Road cost $792 million in total. The U.S. State Department also planned a further $500 million expansion, with completion originally set for 2014 and later extended to July 2016.
The embassy formally suspended operations on the 31st of August, 2021, and transferred limited functions to Doha, Qatar. The chancery building on Great Massoud Road officially closed on the 15th of August, 2021, after Kabul fell to the Taliban.
Chargé d'Affaires Ross Wilson was the final head of mission. The embassy had no Senate-confirmed ambassador at the time of the Taliban takeover. Wilson left on the last U.S. military flight out of the country at 23:59 local time on the 30th of August, 2021.
On the 15th of August, 2021, embassy staff moved to makeshift facilities at Hamid Karzai International Airport as Taliban forces surrounded Kabul. Military helicopters ferried diplomats from the compound to the airport, firing flares to deter rocket attacks. All staff had been relocated to the airport by 7:00 pm local time that day.
A U.S. legation in Kabul was established in 1942, elevated to a full embassy in May 1948. Louis G. Dreyfus served as the first U.S. Ambassador to Afghanistan from 1949 to 1951. Before 1942, Afghanistan was served concurrently by the U.S. legation to Iran.
On the 13th of September, 2011, heavily armed Taliban insurgents wearing suicide vests struck multiple buildings in Kabul, including the U.S. Embassy. At least 7 people were killed and 19 wounded across the city. Several Afghan visa applicants waiting at the embassy were wounded; no embassy personnel were hurt.