I was very young as well at the time, 10 years old. I was at my grandpas house near my grade school for lunch and I was resting on his little foot stool watching tv when the breaking news report came on and said what was happening. I didn't much understand it, but I understood the consequences and that those buildings were full of people just like me and you. 
 
It was a very sad time and I will never forget that it happened for as long as I live.
 
My condolences go out to those who lost loved ones in the terrible event, and those who are stuck with the memory. 
 
R.I.P Victims 

I was at MCAS New River, NC going thru my MOS school in the Marines.  I was also hung over since I had gotten trashed the night before.

I was listening to Howard Stern.  Made me think of the B25 which crashed into the Empire State Building back in July of 1945.  I thought it was one of his usual skits or something until I got into work and saw every TV in the place turned on to the news.
 
Went straight to my armory and we started to plan some relief efforts from across the river.  Spent quite a while on "bridges and tunnel details" and babysitting power plants. 

i remember when i went inside the WTC a month before it was destroyed.  (nostalgic moment )

I was working just outside the River Bend Nuclear power plant, which is more or less right next to the Marathon Oil Storage facility. Then they announced the President was in Louisiana, and possible other targets. Two of those possible other targets were Nuclear Power plants, and Oil Storage facilities. Few minutes later the alerts went off at the plant for security lockdown. I learned just how fast my truck could move on the way home. As most Americans, I was horrified at first, then angered that someone had done this. I was in New Orleans for Katrina, and worked cleanup down there, and as bad as that was. It did not even come close to the feeling of loss as watching the events on 9/11. RIP to those that died, and prayers to those who survived and have to relive it in they're memories.

 
Another thing I recall is the USAF fighter jets flying extremely low around Manhattan and the Hudson (F16's I think?) on the day ...and in the days that followed the sound of those military jets flying patrol over NYC - particularly late at night when there were no other sounds but the deep high-altitude rumble of the jets.. again, quite surreal.
 
It was also fairly common to see the black helicopter gunships - often they would fly low right over our apartment building in Brooklyn, heading towards Manhattan (presumably we were on their assigned flight path). Very different sound from the normal police/news helicopters.
 

A reminder once again to please stay on topic.

I was on the school bus on the way to school. I was a Junior in high school, a high school that was primarily kids with military families (our town is next to a major military base called Fort Carson), and some families also came from military bases only a spits drive on the interstate (in all, there are 5 military bases/establishments in our area). 
 
Anyway, I was really tired, as it was just after 6:50am. I overheard several kids talking. Over the normal noise on a school bus, it was hard to make out exactly what they were saying. Being half asleep didn't help much either. I kept hearing them mention that a plane flew into the World Train Center in New York. It make almost no sense to me. However, I figured a small plane probably crashed in Grand Central. I mean, if any place in New York was going to be called the World Train Center, it would have to be Grand Central.
 
In first class, no one really talked about it. But in second class, the teacher had the TV on. It was then that I got it was the World Trade Center. Made a bit more sense to me. But at the point everyone was in shock. When class started, the teacher turned off the TV and said its best to focus on school and not something that horrible. A good portion of the students objected.
 
By then parents from the nearby bases started showing up to school and pulling their kids out of class.
 
Last two classes of the day, both history classes, kept the TV on while the teachers talked to us about it. It was definitely meaningful for the teachers to actually discuss how the world really is, and why this happened.
 
I later found out that the bases went on full lock down. Students who lived on base with their parents got stuck for hours in traffic before they finally made it on base.
 
My best friend was stationed in Kuwait at the time. I remember him telling me that they suited up in chemical/gas warfare suits, erected make shift barricades at the entrances, then sat there with fully loaded 50 cal machine guns.
 
My dad was working in a skyscraper in Atlanta when the attacks happened. He said that after the general disbelief, they started to evacuate the buildings out of fear that the same would happen to them.
 
But after I got home that day from school, the whole family was glued to the TV. There was some discussion, but we mostly just watched the TV.
 
We tried calling my sister who was in College in Rhode Island at the time. It was difficult to get through, because the phone system simply couldn't handle all the calls going through the nation. Eventually we got a hold of her. Our biggest concern was that she may have gone to the towers that day, as she was always talking about going to visit them 'soon'.

I remember it well. I was visiting my friend and we were sitting in the livingroom watching tv, then all of a sudden the news came on saying that a plane had hit one of the twin towers. I remember it being very surreal and at first i dont think we even realized what had really happened. But unfortunately it was very real.
 
I live in scandinavia, but when this happened 10 years ago, i felt much much closer than you would think.
 
9/11 will never be forgotten.

I had graduated HS earlier that year and was waiting for college to start later that month. My Mom came downstairs, freaking out telling me to turn on my TV. West Coast time zone, so I was sleeping and I was pretty scared just by how upset she was. 
 
Like many others I spent the day glued to the TV, horrified.