It's that time of year once again

[Old Vantaa Man]

when we say: "Al Qaida did this? My arse."

Rich Banaciski -- Firefighter (F.D.N.Y.) [Ladder 22] ... and then I just remember there was just an explosion. It seemed like on television they blow up these buildings. It seemed like it was going all the way around like a belt, all these explosions.

Brian Becker -- Firefighter (F.D.N.Y.) [Engine 28] The collapse hadn't begun, but it was not a fire any more up there. It was like -- it was like that -- like smoke explosion on a tremendous scale going on up there.

Greg Brady -- E.M.T. (E.M.S.) [Battalion 6] We were standing underneath and Captain Stone was speaking again. We heard -- I heard 3 loud explosions. I look up and the north tower is coming down now, 1 World Trade Center.

Timothy Burke -- Firefigter (F.D.N.Y.) [Engine 202] But it seemed like I was going oh, my god, there is a secondary device because the way the building popped. I thought it was an explosion.

Ed Cachia -- Firefighter (F.D.N.Y.) [Engine 53] we originally had thought there was like an internal detonation explosives because it went in succession, boom, boom, boom, boom, and then the tower came down.

Frank Campagna -- Firefighter (F.D.N.Y.) [Ladder 11] You see three explosions and then the whole thing coming down.

Craig Carlsen -- Firefighter (F.D.N.Y.) [Ladder 8] ... you just heard explosions coming from building two, the south tower. It seemed like it took forever, but there were about ten explosions. At the time I didn't realize what it was.

Jason Charles -- E.M.T. (E.M.S.) ... and then I heard an explosion from up, from up above, and I froze and I was like, oh, s___, I'm dead because I thought the debris was going to hit me in the head and that was it.
...
I look over my shoulder and I says, oh, s___, and then I turned around and looked up and that's when I saw the tower coming down.

Frank Cruthers -- Chief (F.D.N.Y.) [Citywide Tour Commander] .. there was what appeared to be at first an explosion. It appeared at the very top, simultaneously from all four sides, materials shot out horizontally. And then there seemed to be a momentary delay before you could see the beginning of the collapse.

Kevin Darnowski -- Paramedic (E.M.S.) I heard three explosions, and then we heard like groaning and grinding, and tower two started to come down.

Dominick Derubbio -- Battalion Chief (F.D.N.Y.) [Division 8] It was weird how it started to come down. It looked like it was a timed explosion ...

Karin Deshore -- Captain (E.M.S.) Somewhere around the middle of the World Trade Center, there was this orange and red flash coming out. Initially it was just one flash. Then this flash just kept popping all the way around the building and that building had started to explode.

Brian Dixon -- Battalion Chief (F.D.N.Y.) ... the lowest floor of fire in the south tower actually looked like someone had planted explosives around it because the whole bottom I could see -- I could see two sides of it and the other side -- it just looked like that floor blew out. I looked up and you could actually see everything blew out on the one floor. I thought, geez, this looks like an explosion up there, it blew out.

Michael Donovan -- Captain (F.D.N.Y.) I thought there had been an explosion or a bomb that they had blown up there.

James Drury -- Assistant Commissioner (F.D.N.Y.) I should say that people in the street and myself included thought that the roar was so loud that the explosive - bombs were going off inside the building.

Thomas Fitzpatrick -- Deputy Commissioner for Administration (F.D.N.Y.) Some people thought it was an explosion. I don't think I remember that. I remember seeing it, it looked like sparkling around one specific layer of the building.
...
My initial reaction was that this was exactly the way it looks when they show you those implosions on TV.

Gary Gates -- Lieutenant (F.D.N.Y.) So the explosion, what I realized later, had to be the start of the collapse. It was the way the building appeared to blowout from both sides. I'm looking at the face of it, and all we see is the two sides of the building just blowing out and coming apart like this, as I said, like the top of a volcano.

Kevin Gorman -- Firefighter (F.D.N.Y.) [Ladder 22] ... I thought that when I looked in the direction of the Trade Center before it came down, before No. 2 came down, that I saw low-level flashes.

Gregg Hansson -- Lieutenant (F.D.N.Y.) Then a large explosion took place. In my estimation that was the tower coming down, but at that time I did not know what that was. I thought some type of bomb had gone off.

Timothy Julian -- Firefighter (F.D.N.Y.) [Ladder 118] You know, and I just heard like an explosion and then cracking type of noise, and then it sounded like a freight train, rumbling and picking up speed, and I remember I looked up, and I saw it coming down.

Joseph Meola -- Firefighter (F.D.N.Y.) [Engine 91] As we are looking up at the building, what I saw was, it looked like the building was blowing out on all four sides. We actually heard the pops. Didn't realize it was the falling -- you know, you heard the pops of the building. You thought it was just blowing out.

Kevin Murray -- Firefighter (F.D.N.Y.) [Ladder 18] When the tower started -- there was a big explosion that I heard and someone screamed that it was coming down and I looked away and I saw all the windows domino

Daniel Rivera -- Paramedic (E.M.S.) [Battalion 31] At first I thought it was -- do you ever see professional demolition where they set the charges on certain floors and then you hear "Pop, pop, pop, pop, pop"? That's exactly what -- because I thought it was that.

Kennith Rogers -- Firefighter (F.D.N.Y.) I figured it was a bomb, because it looked like a synchronized deliberate kind of thing. I was there in '93.

Mark Steffens -- Division Chief (E.M.S.) Then there was another it sounded like an explosion and heavy white powder ...

Jay Swithers -- Captain (E.M.S.) I took a quick glance at the building and while I didn't see it falling, I saw a large section of it blasting out, which led me to believe it was just an explosion. I thought it was a secondary device, but I knew that we had to go.

Albert Turi -- Deputy Assistant Chief (F.D.N.Y.) And as my eyes traveled up the building, and I was looking at the south tower, somewhere about halfway up, my initial reaction was there was a secondary explosion, and the entire floor area, a ring right around the building blew out.

Thomas Turilli -- Firefighter (F.D.N.Y.) ... it almost actually that day sounded like bombs going off, like boom, boom, boom, like seven or eight, and then just a huge wind gust just came.