The morning of 9/11, FDNY Commissioner Salvatore Cassano -- then an assistant chief -- was in the command center at headquarters going over the events from the previous day and what was planned for that day.
With him that morning was Chief of Department Peter Ganci, Chief of Operations Daniel Nigro, Assistant Chief Jerry Barbara and Assistant Chief Donald Burns.
By that night, Nigro would be appointed Chief of Department and the other three men would be among the 343 members of the department killed in the attacks.
As they met, the department radio was on in the background as it always was. Suddenly their ears perked up as they heard a report of an explosion at the World Trade Center.
"We figured maybe there was some work going on and we didn't exactly know what was happening at that very moment, but we figured it was an accident," Cassano said. "Very shortly after that, a report came over that a plane had hit the World Trade Center."
The men followed normal procedures, going into command mode, and began to come up with a plan.
As they prepared to leave, Cassano spotted the twin towers from a window. While he first imagined it was a small plane, he quickly realized it was not. He got into his vehicle and drove to the scene.
"As I was getting out of my car, another explosion took place," he said. "I looked up and saw debris coming and I thought it was just a secondary explosion, but it turns out that's when the second plane hit the South Tower."
He took cover in a nearby garage until the debris stopped coming down and then got back into his car and made his way to West Street.
Cassano said the department was faced with several issues. How they were going to evacuate the building, how they were going to put out the fire and if there were other buildings that needed to be protected.
After reporting to the command post, he received orders to assess the Marriott Hotel and while he was walking there, he bumped into Father Mychal Judge. They exchanged a few words and he continued on his way.
He would find out later that day that his good friend perished in the attacks.
Cassano then went into the Marriott, gave orders to the units already inside and then made his way back out to West Street.
Just as he arrived back to the command post, the South Tower collapsed. The command post was positioned near a garage and they took cover until the debris and dust settled and began to assess what had happened and what the next steps would be.
Ganci gave the orders to move the command post as far north as possible and evacuate the North Tower and went south with a number of firefighters with him to lead the rescue effort.
"We knew we had hundreds of firefighters trapped," he said. "He went to lead that rescue effort because that was what Pete did. He was a leader."
Cassano moved everyone as far north as he could and then made his way back to join Ganci, and that's when the North Tower collapsed.
As debris began to shower down, he started to run north, trying to steer clear of danger. There was a rig nearby and he was able to hide under it until the debris subsided.
He had been injured and was transported by ambulance to St. Vincent's Hospital and quickly got checked out.
"No one was coming there because either it was you were alive or you were dead," he said. "I was probably one of the first ones who got treated and released."
After he was out of the hospital, he went back to headquarters and began to take over operations. Everyone was either at the World Trade Center or missing.
"That's when we started rebuilding that department, that night," he said. "We knew we had rigs missing along with masks and tools and equipment. It was pretty hectic. We didn't know how many people we had missing."
"The courage, commitment, dedication and bravery of the firefighters that day is just unsurpassed by anything I've ever seen in my life," he said, adding that when order were given, no one questioned them.