Ceremonies were held Friday in New York City, Virginia and Pennsylvania.
Friday marks 25 years since the Sept. 11, 2001, terror attacks, which claimed the lives of 2,977 people at the World Trade Center, the Pentagon and Shanksville, Pennsylvania.
Another 9,000 people have died from 9/11-related illnesses over the last 25 years.
Victims' families, first responders and politicians gathered for annual remembrance ceremonies at the memorials in downtown Manhattan, the Pentagon in Virginia, and Shanksville, as Americans across the country pause to remember and reflect.
"9/11 Tribute in Light: Live from Lower Manhattan," a one-hour ABC News multiplatform live special, premieres on Friday, Sept. 11, at 8:00 p.m. EDT across ABC, Disney+, Hulu, National Geographic, ABC Owned Television Stations livestreams and ABC News Live.
The second moment of silence was held at 9:03 a.m., marking the moment United Airlines Flight 175 crashed into the World Trade Center’s North Tower.
The annual reading of the victims’ names is now underway at the ceremony at New York City’s 9/11 Memorial & Museum.
At 8:46 a.m., the first moment of silence was held at the ceremony at the 9/11 Memorial & Museum ceremony. This marks the time American Airlines Flight 11 crashed into the World Trade Center’s North Tower.
The New York City Fire Department lost 343 members at the World Trade Center. In the last 25 years, another 453 have died of 9/11-related illnesses, mainly cancer, from their service that day and during the immediate aftermath.
“It’s a heavy day for the fire department,” Commissioner Lillian Bonsignore told ABC News. “It’s not slowing down, unfortunately. We continue to live they day over and over again.”
The NYPD lost 23 members at the World Trade Center. In the last 25 years, another 469 have died of 9/11-related illnesses.
“We have to remember that the largest crime scene in the world very quickly became the largest race and recovery effort that this city certainly has ever seen,” Police Commissioner Jessica Tisch told ABC News.
She said the “vast majority” of officers working in 2001 are no longer with the department, which “makes it all the more important that we pass their legacies and stories down to the next generation.”
-ABC News' Aaron Katersky
