Just about every contingency the 25 commandos trained for came at them, rapidly, chaotically and dangerously, in their lunge for Osama bin Laden.
They had acted on the best intelligence the U.S. had ever had on bin Laden's whereabouts since he slipped away in the mountains of Tora Bora just under a decade ago. But it was guesswork, too, with the commandos' lives, a president's reputation and a nation's prestige riding on the outcome.
Was the man once seen pacing the compound's courtyard really bin Laden, as it appeared to American eyes? That was just one unknown.
Image: Vehicles are parked inside the compound of a house where it is believed al-Qaida leader Osama bin Laden lived in Abbottabad, Pakistan on May 2, 2011.