Damian Vancleaf and fellow firefighters were among the first on the scene when the Trade Center's north tower was attacked.
NEW YORK (CNN) -- For New York City firefighter Damian Vancleaf, the second Tuesday of September started out routinely. He and other firefighters from Manhattan's Engine Company 7, located just a few blocks from the World Trade Center, responded to a call for a gas leak. They were at the scene when they heard the loud drone of an engine from above.
"We all looked up and saw the plane," recalled Vancleaf. "Something was wrong. You never see a plane in downtown Manhattan, especially that low. I could see almost every detail on the plane. That's why I knew it was way too low. I could see rivets in the plane."
The firefighters watched in shock as the jetliner slammed into the north tower of the World Trade Center and a huge ball of fire shot up into the sky.
"We threw all our gig on the rig and we started to respond, down to the Trade Center," Vancleaf said.
Engine 7 was one of the first fire companies to arrive on the scene.
"I remember taking an extra couple of seconds before running in to make sure we had everything and ... we were ready to go, because this was going to be a big one," Vancleaf said.
Genelle Guzman, an administrative assistant for the Port Authority of New York and New Jersey, was working on the 64th floor of the tower when she felt the building shake.
"I was scared," said Guzman. "They (were) saying an airplane hit the building. But I had no idea where the building was hit."
The plane had struck between floors 96 and 103. Guzman waited for instructions on what to do as the tower above blazed.
'There's another plane!'
Across the East River in Brooklyn, New York City's fire chief, Peter Ganci, and his executive assistant, Steve Mosiello, watched the horrific scene from Fire Department headquarters.
"We saw the smoke billowing, the fire, and that people were in trouble," Mosiello said. "People out there were definitely in trouble."
They raced across the Brooklyn Bridge in Ganci's car, along with Danny Nigro, then the fire department's chief of operations.
"I said to Pete, 'This is going to be the worst day we've ever had.' Little did I know," recalled Nigro.
The three made it to the scene in less than 10 minutes. Ganci set up a command post on a ramp leading to a garage near the north tower.
"We were standing with the chief and we heard somebody yell, 'There's another plane!'" Mosiello recalled. "Then it came into the range of my hearing. And it sounded louder and louder and louder and there it was ... it went right into the building, into (the south tower). Now we have a real problem on our hands. We have two buildings hit by planes. Thousands and thousands of people trapped."
'A sick vibration'
Up in the north tower, Guzman was making frantic calls to the Port Authority police, trying to get advice on what to do.
The 31-year-old native of Trinidad also made calls to her family and friends. She left a message on her boyfriend's voice mail: "Honey, I'm staying inside of the building. I don't know ... we have to wait until somebody comes (to) get us out. Okay? I'll try and call you back again. Bye. I love you."
Meanwhile, at the base of the north tower, the firefighters from Engine 7 arrived and stopped to extinguish flames on some of the people who were rushing from the building. Then they headed into the building with dozens of other firefighters.
"While we were up, operating on the 21st floor, there was a sick vibration in the building," Vancleaf said.
Although Vancleaf did not realize it at the time, the vibration he felt was from the collapse of the south tower next door.
"After that vibration, it was just something that wasn't right, and eventually I heard the order to vacate, to back out, to evacuate the building," he said.
Steve Mosiello (above) was the top aide to Fire Chief Pete Ganci, who perished during the collapse of the north tower.
Chaos on the ground
Down below, the streets were filled with panicked people and clouds of smoke and debris from the south tower collapse.
Chief Ganci and his assistants managed to escape from their makeshift command post and retreat into the basement of a nearby building.
"The basement was full of dust. You couldn't breathe," Mosiello said. "We couldn't find a way to get out. We finally found a staircase and we all got out."
Ganci told his men to set up a command post in a safer location, further north of the disaster. He ordered Mosiello to retrieve some backup. And then the fire chief rushed back toward the scene to help with the rescue efforts.
The order to separate came as a surprise to Mosiello. As the chief's top aide, his job was to protect his boss and never to leave his side. Off-duty, the two were just as close -- they were best friends.
Ganci had helped Mosiello find a home, right across the street from his own, in Massapequa, New York. The two worked on each other's house. They played golf together, betting a dime a hole.
"It was a marriage," said Christopher Ganci, describing the relationship between his father and his top aide. "I don't want to make my mom jealous or anything, but it definitely was. He spent more time with my father than we did."
The two men usually began their day before sunrise.
"I would get up early in the morning, 4:15, put the coffee on, open the back door to my deck, go take a shower, do my routine, and I'd come down and he'd be sitting there waiting for me," Mosiello said. "He'd be drinking his coffee and smoking."
The morning of September 11, Ganci had jury duty and Mosiello was supposed to drive him to court instead of the fire department.
"We're passing one of the parkways that would have brought us toward the courts and I said, 'Do you want to go to jury duty and make an appearance?'" Mosiello recalled. "He said, 'Steve, I have so many meetings today. You know, we just can't get there today.'"
On September 11, 2001, two hijacked airplanes crashed into the twin towers of the World Trade Center. Neither tower proved strong enough to withstand the crashes and both collapsed soon after being hit.
'I'm going to die here'
Vancleaf and a fellow firefighter from Engine 7, Pat Zoda, had followed the orders to vacate the building and made it safely to the bottom of the north tower.
"We just got to the lobby and there was no one there. It looked like the end of the world," Zoda said.
Guzman was not far behind. After waiting almost an hour for assistance, she had decided to make her own way down from her office on the 64th floor. She and colleagues from her office had reached the stairwell of the 13th floor when they heard a loud boom.
"We fell, we fell to the ground," Guzman said. "And then everything started crumbling, faster and heavier, and everything just kept falling."
The building was collapsing on top of them.
Guzman's boyfriend, Roger McMillen, was waiting on a corner a few blocks away for Guzman to come down from the north tower when he saw the building begin to collapse. He and the other terrified people on the street ran for their life as clouds of soot and debris rolled in. He thought Guzman was dead.
Miraculously, Guzman was alive but she was in serious trouble. Her head was pinned between two concrete pillars and her legs were trapped in the staircase. The colleagues who had been with her were all gone. Her thoughts turned to her 12-year-old daughter, Kimberly. She drifted in and out of consciousness until the light peeking through the concrete eventually gave way to darkness.
"I saw it became dark and no one came ... and I'm not hearing any noises." She thought, "I'm not going to make it. I'm going to die here. I'm going to see myself slowly dying."
Mosiello was also thinking the worst about Chief Ganci's fate. The north tower collapsed minutes after his boss radioed him to give his location.
"I kept trying to reach him and I got no response," Monsiello said. "It was so eerie because the chaos of the radios at a fire scene, there's always conversations going on. And after that building came down you heard absolutely nothing. Nothing at all."
'Where is everybody?'
By dusk, the firefighters of Engine 7 began making their way back to their station.
"The first person I saw there was the captain, Captain Tardio," said Vancleaf. "His first question to me was, where is everybody?"
One by one, the firefighters returned. The entire team had escaped the north tower with just minutes to spare before the building came down.
"I believe if we were two more floors up we would have been dead," said Zoda.
Chief Ganci was not so lucky.
His body was later found buried under four feet of debris. Mosiello helped recover his remains from the rubble, then had to give the Ganci family the bad news.
"Here I am, his best friend, his closest friend, his aide, his executive assistant, his driver -- everybody," Mosiello said. "And I'm standing before them and he's not."
At the time, about 4,000 people, including 343 firefighters and Genelle Guzman, remained missing.
Genelle Guzman, with the Port Authority, was in the north tower as it crumbled. She was found and rescued after being trapped for 27 hours.
'I felt the fireman hold my hand'
The morning of September 12, smoke billowed from the pile of rubble that once was the World Trade Center. The New York Fire Department pressed on with the rescue effort, despite its terrible losses.
"The next day ... after I woke up, I started to pray again," said Guzman, who remained trapped under tons of debris. "I asked God to show me a miracle, show me a sign that I'm going to get out of here today and not the next day. And so it happened that I heard noises ... like people moving stuff. And I yelled out and ... someone answered me."
It was 27 hours after the tower's collapse.
"I took a piece of concrete and I knocked the stair above me. And then they heard the knocking and they decided to come closer," she recalled. "And then I put my hand through a little crack ... and I felt the fireman hold my hand. And he said, 'I got you.' And I said, 'Thank God!'"
She was the last person pulled alive from the rubble.
When Roger McMillen received notification that his girlfriend had been found and was at Bellevue Hospital, he thought perhaps they wanted him to come down to identify her body. Instead, he found Guzman alive, although barely recognizable, due to the swelling that distorted her face.
"We both cried," he said.
'I feel guilty every day'
On the Saturday following the attacks, the body of 54-year-old Pete Ganci was laid to rest. The 15-mile procession from the church to the graveyard was lined with civilians and firefighters paying their respects to Ganci -- a leader, a neighbor, a friend, a husband and a father.
"I look at my mom and I see how strong she is but I know she's hurting," said Chris Ganci. "I try to be there for her because my father would want me to be. And my sister ... the first thing she said was, 'Who is going to walk me down the aisle when I get married?'"
Some of Engine 7's firefighters are among those who report daily to help in the grim recovery effort.
"I feel guilty every day, every morning. I don't know why," said Vancleaf. "I guess that's part of surviving something like that. I stood next to people that are no longer here."
After three surgeries and five weeks of hospitalization, Guzman still requires a brace to walk and must undergo grueling physical therapy twice a week. She suffers from nightmares and is disturbed by loud noises.
But she feels extremely lucky. She and McMillen became engaged on November 7 and she is hopeful that she will be able to dance with him at their wedding.
"I'm just so thankful to be here that I can see my life in a completely different direction," she said. "I just want to have a family, be close to my family. And just give praise and thanks for being here."
Ganci's grieving family finds some solace in his legacy.
"Would I want my father here to spend time with, to talk to? Of course," said Chris Ganci. "But he played his part that day. He was a true hero. There's not that many times you can go around and say that your father's a real all-American hero."
Mosiello now drives alone to the fire department each day. But he still rises at 4:15 a.m., puts on the coffee and unlocks the door.
"There isn't a time I don't look over at his house and think about him, think about his family," Mosiello said. "It's getting easier. I'm sure it's getting easier for them. But it will never be easy."