I worked at a radio station and we normally had the station playing throughout the offices.
I remember hearing that a light plane had apparently crashed into the twin towers, but in all honesty no one paid too much attention to it. The fact it was on the radio station was a bit unusual though. However, within about 10 minutes, the engineers started sprinting around the building and we knew something was happening. In all honesty, we thought something had happened to the Queen as they tone of the music started to change and they read out that something was happening in the US and it related to a plane.
The next few hours were a blur. The engineers were frantically getting us set for a major disaster and no one had any idea when, or how, this would pan out. It was an event that absolutely no one could even understand. We went into the state where you play sombre music and the DJ says little. They obviously knew what was happening now was an atrocity. Everyone in the station - apart from those who's job it was to get the programmes out stood watching TVs in silence.
The first 2 aircraft was unbelievable in itself - we were all used to planes being hijacked, but using them as weapons was unthinkable.
When the reports came in the Pentagon was under attack, you cannot explain to anyone how it felt. The Pentagon under attack. No way would any country like Russia, China etc even dream of attacking the Pentagon. It was at this point we were wondering who or what was doing this. If you'd had told me that aliens had invaded, I'd have believed you - it's the only way I can explain how it felt. No one could do that to the US, surely. We also didn't know if the UK was next either. We all felt very vulnerable.
We also had an office in NY and we were unable to call some of the staff out there. They weren't in the towers, but when you saw them collapsing you can't imagine how much debris must be in a building nearly a mile high.
On our TV feed, we also got to see one of the planes before it crashed. We were watching hundreds of people on board a plane, all about to die. It was utterly terrifying.
My parents were on holiday at the time and I was worried sick about them. No one had any experience of this and every one was scared to death of flying. I think everyone on flights around that time was terrified. If you'd had an inkling that someone was doing anything slightly unusual, you'd have absolutely battered them on the plane.
However, me and some friends had booked to go travelling around Los Angeles, San Francisco and San Diego and we still went 2 weeks or so after 9/11. It was an absolutely bizarre experience, one I'll never forget. The security was off the scale and I've never been so scared of "Border Force" in my life. When we were on the plane I checked everyone out I could see. Everyone was suspicious of each other.
We went to Universal Studios in LA and literally I think there might have been around 200 people in. Seriously. We went on each ride, didn't even queue to get on and just went straight back on. We spoke to students who'd booked it months ago and just gone out for as long as their money would last and they were in 5 star hotels as no one else was in them! The Americans were really nice and really surprised and happy we'd gone there though. California is absolutely stunning at any time but if you can go there when there are no tourists, it's even better.
One particularly scary part of the trip was that I was fairly sure that someone stole my passport for a day whilst we were in San Diego. Seriously. Without a passport, I couldn't prove who I was. Without a passport, I could end up in jail and at the time, security was extremely high. The police office we tried to report it to was closed so I had 24 hours without it. "Luckily" it was returned, but I remember feeling extremely vulnerable at the time. I didn't know whether to report it and potentially face time in jail, or just carry on. I carried on.
We also did a trip to Tijuana in Mexico. Going over the border was no problem at all. However, it was a massive mistake. On the way back we had to wait in a queue to get back into the US and we ended up queueing outside in 90 degree heat for 2 hours. The way some people were spoken to in the queue was pretty disgusting to be honest and we were genuinely scared they wouldn't let us back in. I saw men and women - Americans - pretty upset about it all.
Overall, it was a turning point in history and those who experienced it, where ever they were, will never forget that day. It's impact will live on for decades.
The consequences for the world were enormous. Firstly, we invaded Afghanistan and Iraq as a direct result. Secondly, because the economy and markets were spooked by this and the dotcom bubble bursting, it led to lower interest rates and pumping markets which contributed to the Credit Crunch in 2008. Finally, a longer term result of 9/11 is that the US is unlikely to intervene in foreign conflicts and I think this will be one of 9/11s most influential impacts in the longer term.