Firefighters search the rubble of the destroyed World Trade Center in New York on September 11, 2001. Rescuers searched for survivors the day after two hijacked passenger planes slammed into the Center's 110-story twin towers, killing possibly thousands of people. Two police officers were pulled alive from the rubble late Tuesday, more than 12 hours after the attack, raising a ray of hope for others. But eyewitnesses and emergency workers said they were skeptical that many survived. (Shannon Stapleton / Reuters)