WAUKEE, Iowa -- Dawn Rizzi worked just a few blocks from the World Trade Center.
"I saw the plane hit into the towers," she said.
Shocked and in disbelief, Rizzi immediately realized what fate had allowed her to escape.
"I was supposed to be in the North Tower," said Rizzi. "There was a restaurant, Windows on the World. I was supposed to have a breakfast meeting, with, it was a video conferencing and we were with our London office, and 20 minutes before we were supposed to leave, me and my coworker, we received a phone call from London and says that we had to make a change to the presentation."
Those 20 minutes saved Dawn Rizzi's life.
"Just to think that I didn't get to tell anybody, so no one would have known in my family that I was there," said Rizzi.
Dawn's husband, Nick, was a New York City police officer at the time. He had gone off-duty earlier that morning, and was watching the images of the burning buildings on TV from the couple's home in Queens.
"An emergency message began to come across the bottom of the screen, requesting from New York City all off-duty emergency personnel to proceed back to work," said Nick. "I knew I had to go back, but at the same time, I didn't know if Dawn was okay."
So, Nick called his command.
"I spoke to my supervisor and I informed him about Dawn, and I asked him if he would give me extra time before going back, because I knew I wasn't going to be able to concentrate on performing, you know, my police duty without knowing if Dawn was okay."
Dawn would be okay, but first she had to get to safety.
"It was so eerie, because it was beautiful sunshine and in a matter of, like, a minute, it turned to darkness," said Dawn. "It was just dark, the whole downtown, and it was really silent, even though there was thousands of people just everywhere."
Covered in debris from the collapse of the towers, Dawn walked more than seven hours to get home. Before she arrived, Nick got a call informing him that she was okay, so he went to work.
"As I started to get closer and closer to ground zero, I could not believe how empty the streets were," said Nick. "This was a business day in Manhattan, and there wasn't a soul walking in those streets. There wasn't a car passing, and as I got really close to ground zero, I encountered military personnel, the National Guard had already been dispatched. They were literally on the street corners with M16 rifles."
Nick was dispatched to the outer perimeter of ground zero to provide security and relief.
"After the towers collapsed and all that soot and rubble went up in the air, as well as asbestos, we in the NYPD were assigned these air filter masks to walk around with."
Putting his own health on the line, Nick and his colleagues answered the call of duty at America's darkest hour.
"I just went straight through," said Nick. "I mean, I didn't make it home probably for over a week, maybe close to ten days. We just worked and slept at the command."