The streets surrounding Ground Zero were both busy and somber on Saturday morning as thousands of people from many walks of life came to commemorate the anniversary of the September 11, 2001 terrorist attacks on New York nine years ago.

It's the morning of September 11, 2010, exactly nine years since the terrorist attacks at the World Trade Center, now known as Ground Zero. Firefighters at Engine Company 7 stand at attention as the firehouse bell tolls in memory of their comrades, who died that day trying to save others.

For fireman Rocko Angelo Cocciolillo, this is a highly emotional moment.

"I'm sad. I lost 343 brothers down there, nine years ago on this terrible day and I am here to say my prayers and thank God that we are still here and to pray for their families and to never forget, my man. That's basically it. As long as I'm alive I will be down here on the eleventh of September," he said.

Watch Footage of the Ceremonies in New York and at the Pentagon

So, for that matter, will Frank Marquez of Los Angeles, California. As soon as he heard of the attack and its devastation, he quit his job and left for New York to volunteer. He stayed for seven months helping out firefighters and combing through the wreckage at Ground Zero looking for human remains.

"These are my friends. I made friends with these guys nine years ago. I used to feed them. I used to bring food by and drop them off at the firehouse and do that three times a day. We did that for seven months. These people are my brothers, the firefighters of New York, the police officers of New York, and all the first responders that came to New York. We bonded. We're a family now. They've taken me into their fold and I am honored by that," he said.

Marquez says the experience changed his life forever.

"Although my health is failing because of it. I have toxic poisoning. It doesn't mean anything to me. That's the price you pay for taking risks. I knew the deal when I came here. I walked away from my world to come and help. I just started hitchhiking. It took me a week to get here. I started on September 12. I got here on September 18. I hit midtown at 10 in the morning. By 5:30 in the evening, I was passing buckets at Ground Zero. People say 'move on'. You don't move on from something like this. You deal with it on a daily basis as best you can," he said.

Closer to Ground Zero, Sam Mandelbaum of Texas finds both comfort and confrontation at Saturday's commemoration events that include moments of silence, the reading of victims' names, and a swarm of visitors, all of it amid new construction at the site.

"Because it's an opportunity to heal. Because it's been nine years, which is not that long, but any time that anybody comes to this place they have to face the deaths that happened on that day, the deaths that have happened since then because of that day, the way the world has changed the way we have changed, and the way the landscape has changed. And my response is acceptance," he said.

But Bonita Mentis still finds it impossible to accept what happened to her sister, Shevonne, who died in the attacks.

"Some people actually got closure because there was a body. With her, we never got a body or anything, So it's still hard. She was a wonderful sister, a wonderful daughter, wonderful aunt. She was only 25 years old at that time. A full-time student at Borough of Manhattan Community College. She had big dreams. Unfortunately for her, it was not meant to be," she said.

Because of the iconic status it has assumed, it can be easy to forget that Ground Zero was located deep within a bustling community, where people like Robert Mulero live and work. For them, the terrorist attacks were a very local story.

"We saw everything. We saw the buildings come down. We saw people coming out the windows. We felt the vibration, we saw the chaos that was going on. Where I worked ? people were saying, 'My daughter works there,' 'My husband.' We did see people fall out the building ? just falling down. I was afraid of going home. I didn't go home that night. I have to say one thing: after September 11th, strangers wanted to help everybody. I was out in New Jersey and I was in a bar and someone offered me money, food, if I needed place to stay. And this one guy said to me 'do you need to make a phone call?' I said, 'Okay. I'd like to speak to my sister.' And when I called my sister, she started to cry. This is my cousin's daughter, she was killed. She got stuck in the elevator and she suffocated. I feel bad for the mother, and the parents. You are not supposed to bury your kids," he said.

Indeed, Mari Richardsson, a Swedish tourist on holiday in New York with her family, seemed to clutch her own kids a bit tighter as she looked at the place where the World Trade Center once stood. She remembers September 11, 2001 vividly.

"Yes, of course you are sad," she says, "but still you have to find other ways to go ahead and try to make something out of it too, I think."

For many Americans and their well-wishers abroad, both strength and sorrow continue to be intertwined in their memories of the terrorist attacks that shocked the world. But as recent developments related to the 9/11 attacks in New York and their consequences show, both controversy and healing, anger and reconciliation, continue to be vitally relevant themes.