Thomas Von Essen was commissioner of the Fire Department of New York at the time of the attacks. The NYFD lost 341 men at the twin towers.
It started like most other days. I was on my way to the office, on the highway in New York City, when I got the call. A plane had crashed into the North Tower. I was very close to it, so I got there quickly.
As I arrived, I could feel the vibrations of someone who had crashed to the ground. We call them jumpers in New York, but I've never really believed they chose to jump. I think the heat drove them out.
We made a decision not to put fire out; we didn't have the water supply and the damage was so great already. Instead, we focused on trying to get as many people out as possible. Then we heard another explosion. It was the South Tower being hit. At that point, we knew we were under attack.
It got worse as the days went by. You start to assess what it all meant in terms of real life pain and suffering. It took a couple of days to realise that we had lost about 2,700 people. There's all that grief and sorrow to deal with.
It changed all of our lives. There was an excitement to the operational aspects we had to do – repair the city, repair the infrastructure. There were challenges that were interesting as a leader. What wasn't exciting was the dealing with the deaths. So many men were family men. So many men were religious men.
Afterwards, you exhibit behaviour that is different from before. My wife and family tell me that I'm angrier that I ever was. I find myself even more emotional – sometimes ridiculously emotional. The slightest meaning or thought gets me. These last weeks have been a little harder than usual. This year, the anniversary has been exceptionally difficult. It seems like it was yesterday.
Thomas Von Essen is a spokesman for The French Will Never Forget www.thefrenchwillneverforget.com
Shukria Barakzai was born in 1972. She is a human rights activist and Member of Parliament for Kabul. She is married and has seven children
I was in Kabul at home, teaching a small secret school. We had no television. We heard the news on the local radio and later we searched on the BBC. It was really unbelievable.
We understood that America was going to attack. Everyone wore new clothes because they believed their lives would soon be over. People tried to leave but when the attack started it became clear that the US had the technology to find the right people and confidence returned. People everywhere jumped back to their schools, their offices and restarted their lives.
I resumed my studies at university. I also used my newfound freedom of speech to set up the first independent, impartial newspaper called Women's Mirror. Then I got another really important job: drafting the constitution for the country. It was quite an exercise for the men on the drafting committee, listening to a woman and talking to a woman.
I decided to become an MP in 2005. I ran against my husband but the constituents trusted me and voted for me. I ran again in 2010 even though I was tired. Being a reformist and always in the minority is hard.
Lots of positive changes have come to Afghanistan. Those who are casting blame, at least now they can complain about the leadership and no one will punish them. But we lost a golden opportunity and made mistakes: the military agenda, not taking justice issues seriously, corruption and civilian casualties.
I would love to run for President in 2014 – not to be famous, but so a true reformist can lead the country. At the moment I chair the defence committee. It's a challenge but I am trying to show that, for women in power, gender is not the issue but commitment to the job.
I asked my mother when I was four or five when peace would come. I've not yet got that day I am waiting for.
Curtis Applegate, air-traffic controller, was at the New York regional control centre in Ronkonkoma, where he worked the airspace over eastern Pennsylvania and central New Jersey
The first I knew something was wrong was when the two guys behind me started discussing a missing plane. It's rare for that to happen, and they were talking about it as a possible hijack. We eventually tracked the missing flight to NYC and had good radar on it as it was going over the city, but then it suddenly disappeared; just dropped off the screen. We didn't know it had hit a building, so we kept looking for it.
While we were still trying to find that flight, a second plane, United 175, also went missing. Then it started to sink in that something was wrong. We tracked that plane to Manhattan, and saw it was descending rapidly. That was one of the worst moments, because we knew this guy was going to crash somewhere in the city.
For months afterwards, what bothered me was that we didn't realise what was happening sooner. I was also overseeing United 93 that day. It was one of the last flights to leave Newark, but by the time I realised that there was a co-ordinated terrorist attack, he had left my airspace. I kept wondering: if I'd realised sooner and told him what was going on, would that have made a difference? Would the pilot have locked his cabin door?
Later, the makers of the United 93 film hired me as a consultant, and I ended up playing myself in the movie. They did a real good job of showing what it was like that day: the confusion, the chaos. I still remember the moment we heard that the World Trade Centre had been hit. There was this dead silence. I'd never heard the room as quiet as that, before or since. It went on for an eternity. To this day, that moment is scarred on my brain.
Major Will Colquhoun, officer in The Black Watch, 3rd Battalion the Royal Regiment of Scotland. On 11 September 2001 he was just weeks out of officer training at the Royal Military Academy Sandhurst. His regiment was one of the first into Basra
I had always been tempted by a career in the army. We had family friends in The Black Watch. As a 17-year-old potential officer I went to visit them in Hong Kong. It was like rolling back the clock 50 years to the colonial era. They had a great time. That really got me hooked on army life.
I passed out at Sandhurst in August 2001. We were all excited. Aside from military training there was also every chance of doing skiing and rugby tours.
On 11 September, I was on my first week of a Platoon Commanders' course. We were getting ready for a lecture when it came on TV. Everyone knew this was something big. But very quickly it calmed down. We went back to training as normal. At that moment the ramifications weren't that clear – that it was going to change everything. But it changed the tone of what we were doing, the training had more of an edge to it. It was exciting, slightly daunting, but we didn't really know what was coming.
Over Christmas 2002 I was with the army skiing when I got a call to say come back to battalion. Out of the 12 regimental teams that were training about six were called back. Those left behind were not happy.
No one was under any illusion that this was to sort out 9/11. We all justified it in our minds that it was a WMD (weapons of mass destruction) issue. We genuinely thought that was the case. And the humanitarian issue was a major factor. It was seen as a war for the right reasons, but 9/11 simply wasn't one of them.
I remember people throwing flowers at us the day we pushed into Basra. It was surreal but we were kind of expecting it. Then we turned into everything, from policemen to teachers, engineers to politicians, trying to solve the problems. You could already sense by the time we left in June that the honeymoon period was over.
I deployed to Iraq again in Telic 4 [when the Black Watch was controversially sent to assist the Americans further north and lost six men], spent three years in Northern Ireland and then went out with 19 Light Brigade to Helmand (during the fierce fighting of Operation Panther's Claw) in summer 2009.
I have been quite lucky compared to some of my contemporaries who have been on tours of Iraq or Afghanistan every two years. I have had some respite, which has been great from the family point of view.
I met my wife at university. We married in April 2004 and now have three kids. My wife was never under any illusion about army life. We always knew our lives would be dictated by events. 9/11 came along and it had such a major impact but it was almost by the by. In the army you go wherever the road might take you.
Dr Muzammil Siddiqi, the Religious Director of the Islamic Society of Orange County, was in Washington, preparing to meet President George W Bush
I had an appointment at The White House, at 2pm, with a few other Muslim leaders. We'd been trying to meet the President ever since the election, and finally had got an invitation. But this shattered everything. We were immediately worried about a backlash, so I called other Islamic organisations, and we issued a statement within two hours, condemning the attacks.
Three days later, I was invited by President Bush to lead a Muslim prayer at the national cathedral, alongside Christian and Jewish leaders. All the previous US presidents were there. I spoke from the Koran. I expressed our solidarity, and our grief, and our sympathy for the families of victims. Our country saw us standing together, and I believe there was a great feeling of national unity at that time. But then, slowly, Islamophobia grew.
We were against both wars, in Afghanistan and Iraq. We thought a lot of Muslim people would be killed, and a lot of US soldiers were going to be hurt. And that's what happened. The wars dragged on and on, and cost trillions of dollars. Many American soldiers were killed and wounded. It solidified a lot of bad feeling, in the US and in the Muslim world, and hate crimes began to increase, not only against Muslims, but people who looked like Muslims. In fact, the first person to be killed in the US was a Sikh.
Since 9/11, we have done a lot of work in outreach, communicating with neighbours, and with the interfaith community. We started open mosque days, inviting people to visit, so they had no fear of what was going on inside. And we encourage Muslims to talk about their faith. When anything happens, people generalise. They say there is a problem with Islam. So we've become far more active in relations with others, and have worked hard to spread the message that Islam is a peaceful faith. I hope it is working.
Major Stuart Newcombe, an insurance underwriter at Lloyd's and an officer in the 4th Battalion, The Parachute Regiment. The events of 11 September 2001 dramatically changed the Territorial Army he joined and has led to him serving in Iraq and Afghanistan over the past decade
I joined the territorial army in 1989. We trained very hard for a Cold War role. But, to be realistic, we didn't think that much about it on the basis it was relatively unlikely. At that time if was fairly rare to have somebody who had operational experience who was not ex-regular army.
In a platoon of 40-odd guys, only two or three had been on attachment.
Since 2003 the battalion has mobilised men (to Iraq and Afghanistan) for six major deployments, once every two-and-half years in line with our regular battalions.
On 11 September, I was on a Jungle Warfare Tracking Instructors course in Brunei.
I remember watching television for a ridiculous amount of time that day. We pretty much expected the game was going to change, life was going to change.
But I don't think, even then, I realised how much it would change the TA. Everyone imagined a short term surge, we didn't necessarily appreciate how enduring it would be.
I was on Christmas leave 2002 when I heard that I was to be deployed as a rifle platoon commander [in the Iraq invasion] attached to 1 Para. I was a TA officer in charge of a regular platoon that received TA attachments.
There was a lack of familiarity between the TA and regular soldiers, relatively few had worked together. In 2003, their absorption into the regular units happened very, very quickly. Some got their final notification to deploy just seven days before going out to Kuwait.
Luckily in 4 Para most were of a high standard. However, there was a small element of them who enjoyed what the TA was about but had not given that much thought to the reality of going to war.
My most recent tour was attached to 3 Para in Helmand [last winter]. There were 74 soldiers from 4 Para serving with 16 Air Assault Brigade.
The quality of the soldiers serving now is consistently very, very good. If you are joining now, you fully expect to be deployed at some stage. And the regular army is now used to working with them. It is a massive change.
I now have soldiers who want to join the regular army as officers and serve in 4 Para during university to gain experience. Some spend their gap year in Helmand rather than travelling in the Far East.
I think the whole perception of the Territorial Army [in general society] has improved greatly.
You still get people who don't understand the commitment, joke about Dad's Army, but that has diminished greatly. Arguably it has impacted on my career [in insurance] over the past ten years but my employers are supportive.
With regards to the family, it is a bit more challenging because they know we volunteer. I have two little girls and the guilt is unbelievable. Since I returned from Afghanistan my six-year-old has set out rules about how many sleeps I am allowed to be away.
For me personally, 9/11 changed the TA from being a demanding, entertaining, rewarding hobby to an organisation that now trains soldiers to deploy on operations on an almost constant basis.
It has been a lot more challenging but I have definitely got more out of it.
Shami Chakrabarti, director of Liberty, a vocal campaigner on the threat to civil rights caused by post-9/11 legislation
My first day at Liberty was 10 September 2001. I'd arrived at this tiny outfit a little bit dazed, having spent the previous six years working at the Home Office as a lawyer. I'd been taken on to work out Liberty's strategic direction; by lunchtime the next day, there was no more wondering about our priorities.
As I watched the plane hit the second tower, with this sense of pure human horror came another feeling – dread. A dread that there was a chance that the reaction to this attack would make things much worse. And so it proved. The rhetoric of sympathy and understanding gave way to belligerence. Blair and Bush started using the metaphor of war, rather than crime. If you call something a crime you deal with it through the criminal justice system. Where a war demands a different response.
Straight away Liberty was campaigning against the internment of terrorist suspects without trial in Belmarsh. Then control orders. The plans for 90 and 42-day detention. And later against the rendition of terror suspects, torture, the curtailment of free expression.
This fight, the battle against the reactionary measures and those that followed took up my thirties. It's been an incredibly intense decade. I've seen human nature at its best and most forgiving and at its base worst. But I've never regretted making that move 10 years ago.
Captain Lee Woodward, pilot on a BA flight on 9/11. Now director of business development at CTC Aviation Group
On 11 September, I had a flight from Paris to Heathrow. The peculiar thing was, there was a security incident on board. It was unrelated and, it turned out, unthreatening but it was the first time in my career that had happened. Watching the events unfold live on TV a few hours later, it was surreal. A few days later, I had a flight to Barcelona. The mood was very subdued, very nervy. There was a great focus on security. Pilots always go through the same checks as their passengers, so those changes have affected us too.
But the biggest change has been on board. The door between the flight deck and the cabin has to be locked. In order to access the pilot, the cabin crew need to press a call button which activates three cameras. That way we can check who it is. Before it was installed, we were looking through the peephole every time they needed us. I used to fly to Orlando – we would have 20 children come through the flight deck during a journey. Now I work in pilot recruitment, I see the difference. Students haven't had that experience.
Interviews by Guy Adams, Lianne Gutcher, Alice-Azania Jarvis, Terri Judd, Samuel MustonReuse content