lead photo Members of the Army's 10th Mountain Division hug a wall as they come under fire in the Shahi Kot valley. The resistance they met transformed a carefully planned operation into a dangerous fight that trapped one group for 18 hours.; PHOTOGRAPHER: JOE RAEDLE / Getty Images; American troops prepare to board a CH-47 Chinook helicopter as they head into battle in Afghanistan. The big transports are dangerously vulnerable to groundfire, especially during landing.; PHOTOGRAPHER: JOHN BERRY / Newhouse News Service; On the ground, 10th Mountain Division soldiers call in mortar fire on enemy positions. Al Qaeda and Taliban fighters were holding their ground, rather than quickly slipping away as they had in earlier engagements.; PHOTOGRAPHER: JOE RAEDLE / Getty Images; An Army soldier makes use of his knife and a sheltering rock to mark off the victims of his mortar team. He put the total at more than 40.; PHOTOGRAPHER: JOE RAEDLE / Getty Images; Soldiers from the Army's 10th Mountain Division blast open the door of a dwelling as they move through an Afghan village in the Shahi Kot valley looking for enemy enclaves.; PHOTOGRAPHER: JOE RAEDLE / Getty Images; Members of a U.S. infantry regiment carry a comrade injured by shrapnel from a rocket- propelled grenade. The troops sometimes found themselves pinned down, unable to counterattack because the enemy was out of range.; PHOTOGRAPHER: WARREN ZINN / Army Times / Pool; Col. [Frank Wiercinski] speaks to soldiers who had returned from the fight. Many of them had never been in combat before the Afghanistan operation.; PHOTOGRAPHER: MIKHAIL METZEL / Associated Press; The door gunner of a Chinook helicopter looks out over the rugged Afghan landscape. The heavily armed copters were a vital part of the Operation Anaconda attack strategy.; PHOTOGRAPHER: MIKHAIL METZEL / Associated Press / Pool; The body of an enemy fighter lies on a hillside after Operation Anaconda's deadly encounters. Eight Americans were killed in the operation. "I don't think anyone in the Army expects bloodless victories," one officer said.; PHOTOGRAPHER: MIKHAIL METZEL / Associated Press / Pool; GRAPHIC: Overview of the Operation, LESLIE CARLSON, RAOUL RANOA / Los Angeles Times