On June 28, 2005, when Navy Seals tried to capture the valley's Taliban commander, they were quickly attacked by as many as 150 fighters. A helicopter sent to rescue them was shot down, and 19 U.S. forces died -- one of the single worst days of the war.
A month and a half later, Marines tried and failed to capture the commander again. Ten marines were wounded in the firefight.
American troops were finally able to establish Korengal Outpost in April, 2006 in an abandoned lumber yard. Today, the owner of the mill, Haji Matin, is now one of the main insurgent leaders in the valley.
"The enemy came because of the bases," says Fazlullah Wahidi, the governor of Kunar province, where Korengal is located. He called the pullout "a very good thing" and "the wish of the people."
The pullout was conducted over the last few weeks with 84 helicopter runs -- every one at night, when insurgents are less able to shoot helicopters down.
The fighting was so intense, one soldier was photographed shooting in his boxer shorts and flip-flops, having rushed from his bunk to help defend the base from an attack. Specialist Zachary Boyd joked that he may lose his job because of the photograph, which won photographer David Guttenfelder a World Press Photo award.
Vanity Fair published more than 14,000 words about the valley. The writer, Sebastian Junger, and the photographer, Tim Hetherington, also filed a 20-minute story for ABC's Nightline and won an Alfred E. DuPont award, one of television's most prestigious.
The media attention extended to "Call of Duty 2: Modern Warfare" a video game that featured a Korengal firebases. The game sold 4.7 million copies in 24 hours -- one of the most successful entertainment releases ever, regardless of genre.
But all that attention was, in some ways, outsized. U.S. commanders now say the valley never was as important as it seemed, and despite the loss of life, McChrystal and his team clearly wanted it closed.
"The thing is that in a counterinsurgency strategy, it's about the population. And in the Korengal valley, there is no population center," says Taylor.