But even this vital work must stop to remember the thousands who are lost somewhere in these mountains of debris.
Assistant Fire Chief Frank Fellini has been at Ground Zero since the first hours of the attack. "Almost everyone knew someone. I've met five or six firefighter fathers looking for sons and sons looking for their fathers."
48 Hours was granted unprecedented access to both Ground Zero and the command center of New York's Office of Emergency Management. An army of 20,000 city, state and federal workers as well as volunteers are on the front lines, carefully sifting through debris.
While Mayor Rudy Giuliani has been leading the public charge, his top general is an unassuming career bureaucrat named Richard Sheirer.
Sheirer, a father of five who has worked for the city for 34 years, is director of the mayor's Office of Emergency Management, the agency that is the nerve center of the rescue-and-recovery effort.
"Our job is to coordinate the many agencies," he says. "We have well over 100 agencies and usually 300 to 500 people here 24 hours a day."
Sheirer's job has been to make tough decisions over the past 17 days. On Sept. 11, for example, after the two planes hit the two towers, he asked the police to crash their helicopters into any other planes that might be attacking the towers.
"There are a lot of decisions you have to make and we were all making, that when we get to sit down and think about them, they will haunt us," he says.
The city's original command center was destroyed when World Trade Center Number 7 collapsed hours after the twin towers fell. Within 48 hours, Sheirer and his people found and built a new command center inside a massive pier.
Engineers pore over old maps and create new ones; the FBI tracks its investigators in the field; the sanitation department directs its trucks at Ground Zero, and a weather station watches approaching storms. It's an impressive operation, but Sheirer is modest about it.
"I'm not a hero," he says. "I'm just a guy who does his work. The real heroes are down at the World Trade Center who work 22 hours a day."
Some of those heroes are about to pull down what's left of one of the twin towers. By early evening, the top of the wall comes down. As night falls, Ground Zero becomes a dramatic landscape of destruction bathed in stadium light.
Sheirer finds the place painful. "There are a lot of friends of mine still in there, fellows whose fathers are friends of mine and I want to give them the dignity and respect they deserve," he says. He has been touched by efforts from all over, including one resue team who spent its own money and drove 58 hours with no pay to work there.
Everyone is on a mission, he says: "Twenty-four hours a day you come down here and you think its high noon, and that's the way it's gotta be."
It's 2:45 a.m. Wednesday, and the search goes on. On one pile of debris workers believe someone may still be alive. But on this night, the grim reality for the searchers is finding only the remains of five firefighters. Sheirer is realistic about the chances of finding survivors: "It would be a miracle but I like to believe in miracles. Everyone wants nothing more than to hear there's someone alive but it would take a miracle."
It's 6:38 a.m. Wednesday, a bright and beautiful morning; just as it was on Sept. 11. Since then, New York has changed.
The city is now being run from Pier 94, 73 blocks north of Ground Zero. There, Eddie Gabriel is very busy. Gabriel runs the operation dedicated to finding the missing, investigating the crime and restoring the city to normalcy. That day, for the first time since the attack, the city is willing to help families of the missing obtain death certficates.
Says Sheirer: "These people work 18 to 20 hours a day, come and every day, and deal with the same thing over and over. Sometimes this stuff can make you numb. But they understand what they have to do and they're very good."
At Ground Zero, the search for any sign of life goes on. It is a grueling, difficult task.
"I haven't seen anything like this since 1968. I was in the war," says Vietnam veteran and sanitation worker George Grivas, who is working there. "I was in the Tet offensive, I was in the Ashua Valley and I was at Hamburger Hill when it was overrun, and this is worse."
Today, Grivas is cleaning rubble from the streets. "Whatever they ask us to do, we do it," he says.
Normally, ironworker Ted Standis builds skyscrapers. Today he is taking one apart. He has seen a few body parts during his work. "You try to stay focused on what you're here for and your purpose," says Standis, who is from Long Island. We all got a job to do and that's how I try to deal with it. We want to rebuild the city and get back to normal."
At the command center, the cast of the Sopranos has come to boost morale. Gabriel is more impressed by a schoolteacher's letter from Pennsylvania. "My daughter is two years old, I know I have brought her into a different world than what it was before," he says, crying.
John Pickwood lives in Harlem. He has been hauling trash for nine years. For 15 days, he has been carrying the World Trade Center. "This is something I am going to tell my son and he is going to tell his kids that I worked and I did my best to try and help," he says.
Along the route, people hold signs and flags, and yell out support. "That's the best part to me," says Pickwood. "When you have people out there supporting you. Whenever you get a little tired or dreary, that gives you an extra oost. Run right back and do another one."
It hasn't been easy: "I had a piece of a fire truck, and I know that was somebodys father, somebody's son in there. Words just dont describe the feeling of having something like that in your truck."
Debris is taken to a barge. Before it's dumped, FBI agents look for evidence. They even soak the debris just in case a black box from one of the airliners is inside. Water causes a black box to ping. Hearing no sound, the FBI allows Pickwood to dump his load into a barge. Next stop, the final resting place for the World Trade Center, the Fresh Kills landfill in Staten Island.
"Basically being out at Fresh Kills is an eerie feeling because to me it's like being at the graveyard of the World Trade, because you have got all the debris and its all spread out," says Pickwood. "And it's such an eerie feeling being up there."
Pickwood will be working this job for months to come. "Long time, very long time, just to remove the debris, 180 to 200 days. Right now, my focus is on the moment, day by day," says Sheirer.
It's 6:30 a.m. Thursday. By all outward appearances, the neighborhoods outside Ground Zero are returning to the routines of everyday life. Sheirer welcomes any sign of normalcy: "It's gratifying. It shows the resiliency. It shows people are very strong, can be very strong."
At the ruins this morning, a group of pilots and flight attendants, representing United Airlines and American Airlines, came to pay tribute to their lost colleagues. Roses were thrown into rubble, each representing one of the flight crew. The other heroes of this tragedy pause to watch, reminded yet again of the human cost of the terrorist attack.
It's now 8:48 a.m. Thursday, the end of the 48 hours here at Ground Zero. In two days, these crews have removed more than 12,300 tons of debris. It will be at least six months before the rest of the World Trade Center is gone.
"But we'll rebuild," says Scheirer. "This is New York, and we'll have something here that people will be proud of."
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