The response to the al Qaeda attacks on America was a military campaign unlike any in U.S. history.
Just 200 American soldiers on the ground for most of it — guiding massive U.S. air power and improvising as they went along — toppled a government and defeated an army in less than two months.
Never before had special operations teams played such a huge role in an American war. They turned ragged bands of Afghan militiamen into a conquering army.
The lessons they learned promise to reshape American warfare forever.
Only now are these soldiers sharing their experiences. Most still insist we not use their full names to protect their families. But here is a glimpse at their story.
On a moonless night, U.S ground forces draw first blood.
It's a highly visible show of force, grabbing for just a few minutes a lightly guarded command post and airfield 60 miles from Kandahar. It is, in part, a diversion.
That same night, 300 miles to the north, two special forces "A" teams — each with about a dozen men — are secretly dropped onto remote mountainsides to establish the U.S. military's first contact with a group of Afghan warlords. They are known as the Northern Alliance and have been fighting the Taliban for years.
These elite American troops have never set foot in Afghanistan. They do not know the languages or the leaders. Only a handful of CIA operatives are on the ground ahead of them.
But these soldiers — mostly Army special forces — make an immediate impression on skeptical Afghan allies.
"We were like, where do you want the bombs? And they were like, yeah right. Like you can have a plane here in 10 minutes," said a special forces medic. "Ten minutes later a plane was coming in overhead, dropping bombs …. You want to talk about immediately establishing rapport with these people."
Just 17 days after U.S. soldiers arrive, the first major offensive of the war begins high in the mountains south of the strategically important town of Mazar-e Sharif.
"The terrain was so forbidding and high you simply couldn't cross it with vehicles," said a special forces colonel. "We wound up moving on horseback along with small donkeys carrying American equipment."
Sitting on mountain ridges a mile or less from the enemy, special operations teams using lasers and GPS coordinates begin calling in airstrikes, methodically shredding the Taliban front line.
After five days of intense fighting, Mazar-e Sharif falls.
News of this victory has a dramatic impact throughout Afghanistan, energizing anti-Taliban forces across the north who have spent years sitting in trenches, begging the United States for help.
By now half a dozen Afghan factions in the north have been joined by American teams. There are still only 75 U.S. soldiers on the ground.
In one 24-hour period, just three days after the collapse of Mazar-e Sharif, three major cities fall — Herat in the west, Toloqan in the north and finally the capital, Kabul.
"We pretty much continuously bombed 24 hours a day," said a special forces sergeant named Greg. "As soon as one aircraft left, another one would come in. Sometimes we'd have them stacked up seven deep."
The day after Kabul falls, the U.S. military sends its first small team into the mountains of the south, near the town of Tarin Khowt. This is where the Taliban has its roots and greatest strength.