I was sitting in my "Applied Internet Technologies" class. I don't remember hearing a BOOM, but it's not unusual for brief, loud sounds to go off in NYC. When I left class at about 9:20am, I noticed everyone on Mercer Street standing still and looking in one direction. I didn't know what was wrong, so I looked down the street and didn't see anything unusual. Then I looked up and, in the distance, was the surreal image of one of the towers consumed in black smoke. I was speechless. Even though I used to work in WTC, I never really notice it as anything other than a backdrop on the skyline. I then noticed the other tower in the same shape. I also noticed things flying around the buildings like glitter. It took a while, but I realized they were paper and other debri ejected from the explosion. I knew it had to be a plane, but I was so dumb-founded that I didn't consider it an attack. Then I heard over someone's car radio that the Pentagon was also attacked. With Manhattan locked down and unable to use any phones, I went to my next class. When class was over, I went back to look for the buildings but they were gone.