This question originally appeared on Quora.
Answer by Jonathan Weinberg, founder and CEO of AutoSlash.com:
I arrived for work that morning on the 77th floor of World Trade Center Tower 2 around 8 a.m. It was a bright, beautiful morning, and you could see seemingly forever out the floor to ceiling windows of the building. My company had offices on the 77th and 78th floors. My office was on the 77th, facing the north tower.
I was standing in the hallway outside my office talking to a co-worker when I heard a tremendous explosion at 8:46 a.m. I looked into my office (office wall was floor-to-ceiling glass) and saw a gaping hole in the south side of WTC1. We had no idea what had happened. No part of the plane was visible (it had hit WTC1 from the North—the opposite side from where my office faced).
Eventually, word filtered in from somewhere that it was a plane that hit the building. We didn't know whether it was a commercial jet or a private plane like a Gulfstream. It also did not occur to me at the time that it was a terrorist attack. I just assumed it was a terrible accident.
At some point, I saw people appear at the edge of the gaping hole. Smoke was pouring out, and while I don't recall seeing much in the way of flames, it was clear that there was a raging fire going on inside the building. I saw a number of people jump to their death, desperate to get away from the heat/flames.
It's hard to express what I felt at that point, because I can only describe it as shock. Your mind cannot really comprehend what is happening—almost an overload state. You see it with your eyes, but you are somehow mentally detached from it at the same time.
I called my wife to let her know what was happening. She was just walking out of Penn Station on her way to work. I quickly apprised her of the situation and told her that within a few minutes there would probably be pandemonium as people learned what had happened. I assured her that I was OK, and my building was not impacted. I told her I'd call her again when I could.
Many of my co-workers began to leave the building immediately after the plane hit. For various reasons, I decided to stay. This was partially because I believed that it was an accident, and I was in no immediate danger. I was head of technology for a financial information firm at the time. Based on what I was seeing, I figured it might be days or weeks before we could return to our offices, so there were many things I needed to attend to so that operations could be moved to an off-site location.
At some point, I left my office and took the escalator in our space up to the 78th floor. We had a large conference room there with a projector and cable TV, so I wanted to get the news on to see what was happening. I turned on CNN. Information looked pretty sketchy, but I decided to return to 77 to inform my remaining co-workers that I had TV coverage on upstairs if they wanted to come up.
I returned to my office and decided to call my mother. A few seconds after hanging up the phone at 9:03 a.m., I felt a violent jolt and then a falling sensation. I remember thinking that the building was coming down, and it was the end. The impact caused the building to sway heavily. It was actually designed to sway to a certain degree as the towers have to withstand high winds on a regular basis, but this was far beyond anything I'd ever felt before.
Eventually the building stabilized. Much of the ceiling had come down, and I could feel the breeze from blown out windows on the other side of the floor. This felt oddly disconcerting since none of the windows were designed to open in the WTC.
At that point, I honestly didn't know what had happened. Strangely enough, my first thought was that WTC1 somehow exploded, and what we experiencing was the impact of that.
I found myself outside my office with a number of co-workers. There was a ton of dust and debris in the air, and the electricity was out. While I was covered in dust and other particles, I was not injured. We (about ten of us) made our way to the stairwell on the NE side of the building.
Upon arriving at the stairwell, we ran into some people who had apparently just come down from the 78th floor. One woman had a severe laceration on her arm. While the wound was quite serious, it did not appear to be life threatening. There was some brief discussion about going up (I cannot recall why), but the injured woman or someone she was with mentioned that everyone was dead on the 78th floor.
I later found out that United Airlines flight 75 had slammed into the southwest face of the tower, creating an impact hole that extended from the 78th to 84th floors. Apparently the conference room that I had been standing in just a few minutes before was now obliterated. Had I decided to stay up on 78 instead of returning to my office when I did, I would not be alive today.
Tragically two co-workers who I considered personal friends apparently took an opposite path that day, making their way from the 77th floor to their offices on the 78th floor just before the impact. I never saw them again.
Seemingly insignificant decisions a person made that day determined whether they lived or died. It's still something that's a bit hard to fully come to terms with.
Unbeknown to me at the time, my wife had arrived at work at the Midtown financial firm where she worked, right around the time my building was hit. The WTC towers were clearly visible from the trading floor of her firm. While we'd spoken earlier and she knew I was OK, that was before the second plane hit WTC2. She knew I was still in the building at the time, and she knew what floor I worked on, so at that point, she had no idea whether I was still alive.
Once we got into the 77th floor stairwell, I recall jet fuel pouring down the stairs. I mentioned previously I was definitely in some form of shock at that time and not thinking rationally. Having worked as a baggage handler at JFK airport for a summer (ironically for United Airlines of all companies), I knew what jet fuel smelled like. Still, I could not put one and one together and make the connection that a jetliner had just crashed into the building only a few feet above my head and split open, spilling the contents of its fuel tanks into the building core.
We slowly made our way down the 77 flights of stairs. A woman there who worked for me at the time was about six months pregnant, so we went slowly in order to stay with her and help her down.
At some point, I remember passing a number of firefighters heading up the stairs. They had a full set of gear on, and they looked weary and frightened, yet they continued up past us. It's hard to put into words what I feel for the firefighters who sacrificed everything that day in order to try to help others. Reverence is about as close as I can get.
Eventually, we exited the stairwell and made our way into the mall connecting the WTC complex. I recall thinking that we were still alive and basically were out of danger. It was then that I saw police officers or firefighters yelling and waving at us frantically to get out of the building, and we quickened our pace.
We exited the mall in the northeast corner near the Millennium hotel. We were standing on the street, and it was chaos. I was with a colleague and my boss at the time. There was debris falling off the building, and my boss suggested we get out of the area.
We began walking north. We had gotten maybe five blocks away when we heard a large rumble and saw a massive dust cloud to the south of us from the direction we came. Word eventually filtered up through the crowd that WTC2 where my office resided had just fallen. It was a strange and surreal experience. Thoughts flooded through my mind like, how many people just lost their life? Do I still have a job? Even a mental inventory of the things that were in my office that no longer existed.
Words with my co-workers which I cannot recall were exchanged, and I decided to set off on my own to try to get home and reach my family to let them know I was OK. I eventually walked over the Williamsburg Bridge, caught a bus in Brooklyn heading for Queens, and then flagged down a gypsy cab in Queens to take me to my home in Port Washington, Long Island.
I eventually got through to my family via phone to let them know I was safe. I also spoke with the president of the company who was down in Florida at the time. He later told me that I was speaking very quickly and not making much sense. I guess the events of the day had taken their toll on me.
I made it home a number of hours later. My mother-in-law was there with my daughters, but my wife was still trying to make her way home. I walked in and hugged my two daughters like I had never hugged them before.
The rest of the night was mostly a blur. I spent most of it on the phone trying to account for every employee in the company. It was emotionally draining, but necessary work. I think I collapsed for a couple of hours, and then was picked up by one of the guys that worked for me to head to Philadelphia where my company had a smaller office.
I recall driving down the Brooklyn Queens Expressway and passing the downtown area, seeing a massive plume of smoke still rising from the WTC site. I can only describe it as surreal.
At some point during the trip, I received a phone call from a relative of an employee who had not yet been heard from. I tried to remember where and when I had last seen the person. It was one of the most difficult and emotional conversations I've ever had in my life.
We arrived in Philadelphia later that morning to ensure that we had accounted for all of our employees to the best of our ability, and then to set about the task of trying to resurrect a business that was basically in tatters.
I still had not had a chance to really process what had happened, but I realized that unless we immediately got to work, hundreds of people were going to lose their jobs.
It wasn't until later that night when I checked into my hotel, about 36 hours after it had all begun, that I had a chance to turn on the TV and watch a full account of the events. Sitting there in front of the TV, it was like a floodgate had opened, and my mind finally had a chance to deal with the tragedy and all the emotions that went with it.
Recently, Osama Bin Laden was killed in Pakistan. As a survivor of the 9/11 attack on the WTC, I'd like to personally thank the U.S. armed forces, our intelligence community, and President Obama for their relentless pursuit of both Osama Bin Laden as well as other extremists who carried out acts of aggression against Americans.
As President Obama pointed out, the American people did not choose this fight. It came to our shores and started with the senseless slaughter of our citizens.
I lost four friends and co-workers that day who will forever be in my heart. I try to live every day to the fullest, to honor their lives, and the lives of others who perished that day. While nothing will ever bring back our friends and loved ones, it's a testament to the resilience and fortitude of America's people that we were finally able to gain some measure of closure following this dark event in our country's history.
We must remain vigilant, and most of all, never forget -- both to honor those we lost, as well as to protect our loved ones, fellow citizens and future generations from similar tragic events.
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