NEW YORK -- Two decades after one of the most horrific days in American history, hundreds of people gathered at the Intrepid Air, Sea & Space Museum in Manhattan in an effort to make a positive difference in the world.

Commissioner Rob Manfred and approximately three dozen Major League Baseball employees were among the 500 people donating their time on the 20-year remembrance of the Sept. 11 terror attacks, packing meals that will be distributed by City Harvest.

It was all the work of 9/11 Day, a non-profit organization that organizes the annual Sept. 11 National Day of Service as a tribute to those who lost their lives or were injured in the attacks, as well as those first responders who rose in service on that infamous day.

“Every year, the memories of what it was like for 9/11 and for the period of time afterwards just kind of comes flooding back for me,” Manfred said. “I'm not sure it will ever change; it hasn't in 20 years and I think it will probably be the same for me for the rest of my life.

“9/11 is a special thing, particularly for New Yorkers. We just wanted to find an activity for our employees where we could give back a little bit and participate in the National Day of Service.”

Three members of the 2001 Mets -- Edgardo Alfonzo, Rey Ordoñez and Glendon Rusch -- were on hand for the event, as was Willie Randolph, a former Yankees great who served on the team’s coaching staff that season.

“I was only here for two and a half years, but I always feel like a huge part of New York is in my heart,” Rusch said. “I love coming back to this city. I always feel like I'm a Met forever and a New Yorker forever.”

Randolph, a Brooklyn native who played 13 of his 18 big league seasons with the Yankees, still gets emotional when he thinks back to that tragic day in 2001.

“I just can't believe it's been 20 years,” Randolph said. “I remember it so vividly, like it was yesterday. Just to be here today, when they called me, I needed to come and help out, no matter what it is.”

One year after the attacks, Jay Winuk -- whose brother, Glenn, had been killed at the World Trade Center -- and his friend, David Paine, set out to honor those who lost their lives in a meaningful way. They started a grassroots initiative to try transforming Sept. 11 into a “day of doing good,” attempting to rekindle the spirit they had seen in the aftermath of the attacks.

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“Everybody focused on their common humanity; we came together as a country and came together as a global community,” Winuk said. “Anybody who was alive and old enough at the time remembers the amazing outpouring of compassion at the time. … We had felt we needed to kind of turn the anniversary some; to help the nation focus on unity.”

Their small initiative grew each year, leading to President Barack Obama and the United States Congress joining to designate Sept. 11 as a National Day of Service and Remembrance under federal law. That day, now known widely simply as “9/11 Day,” has become the largest day of service in the country, with more than 30 million people participating annually.

“It's amazing to me to see how organized entities have rallied around this,” Winuk said. “It’s the importance of the individuals who come and volunteer like so many volunteers today, but we couldn't do it without the funding and the organizational support that we get from MLB and so many other entities.”

Baseball played a significant role in the country’s healing in the weeks following the attacks, especially in New York. Both the Yankees and Mets did their part to help the community in a number of ways, while the return to play gave people a nightly diversion from the harsh reality they were living.

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“One thing that sticks out is the way we came together as a team and as a group of guys, tried to help out in any way we could to get back on the field and provide a little bit of healing for the fans that were hurting as much as they were,” Rusch said, recalling the Mets gathering in the Shea Stadium parking lot to pack trucks with supplies.

“I think it made us feel good, like we could be a tiny part of something. A bunch of small gestures add up to some big help. The people -- the first responders especially -- seeing us out there helping and working any way we could, it was a big help for everybody.”

The Yankees made numerous visits to hospitals and armories, where families were anxiously awaiting word on their missing loved ones.

“What we did during the crisis, going down to different armories and to the Javits Center, being with families and trying to do anything to help ease the pain, it’s all we could do at the time,” Randolph said. “We were down there with families and you can see that they appreciated us being there, showing love and showing our support.”

The Mets hosted the Braves at Shea Stadium on Sept. 21, marking the first game back in New York following the attacks. Mike Piazza’s eighth-inning home run off Steve Karsay sent goosebumps down the spines of everybody in attendance and watching at home, marking one of the game’s most memorable moments of the century.

“It was a somber night, but I also think it was a night that marked the beginning of a return to normalcy,” Manfred said. “I think baseball played an important role in terms of giving people a distraction from the grief associated with 9/11.”

“Baseball helped me as a family member try to slowly bounce back from the tragic loss of my brother,” Winuk said. “I'm a great baseball fan, a great Yankee fan, and it was something that I could turn to. … The country just yearned to try to get back to normalcy, to have something to root for; baseball was certainly right at the top of that list. It meant a great deal to me and it was evident it was meaning a lot to other people, as well.”

For more information on 9/11 Day, visit www.911Day.org