There will be memorial events held throughout the weekend at the One World Trade Center in New York City near Ground Zero.
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Tributes to fallen heroes are also underway locally. Action News spoke to one family who lost a son during the attacks.
"Sometimes it's like five minutes ago, and other times it is like, 'Did it really happen?' And other times, I know it is 20 years," said Judi Reiss of Yardley, Pennsylvania.
She and her husband Gary say it feels like 20 years of pain. They lost their son Joshua in one of the towers.
"I don't hide it. I don't want to forget it, and I hope I don't forget it after I pass on," said Gary.
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Like so many other families, 20 years later, they will spend time reflecting on the loss of their loved ones. For this family, time does heal, but they say the heartbreak never really goes away.
"It is really painful. It is physically as well as emotionally. It felt like sometimes somebody was cutting me in half with a knife. It was severely painful, and it still is," Judi added.
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The Reiss family will attend a remembrance ceremony at the Garden of Reflection Saturday at 8:30 a.m. in Lower Makefield.
It's one of the largest memorials in the area and pays tribute to the nearly 3,000 lives lost, with special recognition to the 18 Bucks County victims.
Judi will play a role in the remembrance ceremony.
"We are doing bios of all 18 Bucks County victims which will be on display. I want people to remember all of us, all of our lost ones, as people, not as names," she said.
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There will be other services across the area. The University of Pennsylvania held a 9/11 tribute Friday.
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Attendees were given flowers as a sign of remembrance and hope. The event ended with a moment of silence for the Penn alumni.
"We honor the 16 Penn alumni who were killed that day. We grieve in solidarity with family members, the spouses, the children, and parents," said University of Pennsylvania President Amy Gutman.
The Reiss' hopes the other 9/11 victims are also never forgotten.
"People forget that is not just us, but now, even our grandchildren are going to have to hear what happened, and it is a lot...it's a lot to carry," said Judi.