At 9:37 a.m. on September 11, 2001, American Airlines Flight 77 banked sharply, then dove at 400 miles per hour toward the heart of the U.S. military.

Richard Spencer was an Arlington dispatcher who took the first 911 call. The woman was in shock.

“The only thing she could tell me was, my God, my God, it’s down,” Spencer recalls. “I could see that every single phone line in the communication center was lit up. Something big had happened.”

The first Arlington firefighters arrived at the crash site within minutes. Mimi Konoza got there about five minutes after the plane struck. “There were bits and pieces of aircraft everywhere,” Konoza says.

Dozens of first responders who raced to the Pentagon after the 9/11 attack marked the 20th anniversary at a ceremony at Arlington Fire Station 5. Located just across I-395 from the Pentagon, it was the station nearest the attack.

James Schwartz was assistant fire chief at the time; he arrived nine minutes after the attack, and directly oversaw the fire department’s response at the Pentagon. That day, he says, the most powerful military in the world was dependent on its local fire department.

“The institution of the Department of Defense, the Pentagon, a building with 26,000 people in it, needed us.”

It helped, he says, that the Arlington County Fire Department already had good working relations with staff at the Pentagon. In fact, they’d responded to a fire at the Pentagon three weeks before 9/11, Schwartz says.

Spencer says the next call he took, after the woman in shock, was from the Pentagon dispatch center. “They told me, send me everything you got, and they hung up on me.”

Many firefighters that day “self-dispatched,” heading toward the plume of smoke on their own when they couldn’t get through to dispatchers. Radio channels were jammed with traffic, as were emergency phone lines.

Konoza says the attack site was a battlefield.

“I’ve never seen so many bodies in one place, or body parts in one place,” says Konoza, who spent 17 years as an Arlington firefighter.

There were 189 people killed in the attack on the Pentagon, including the five terrorists aboard Flight 77.

Konoza worked at the attack site every night for the next three weeks. She and other first responders have spent years working through the trauma.

“I can honestly say today that the ghosts are gone, and I’m feeling very proud of what we did on that day,” Konoza says.

At the Arlington ceremony Saturday, bagpipes played as firefighters and police officers laid roses on a steel beam from the destroyed World Trade Center that is now on display outside Arlington Fire Station 5.

In the District, Mayor Muriel Bowser and members of the D.C. Council held a ceremony outside a firehouse on 13th St. NW. They honored the 11 District residents and three D.C. teachers who died aboard Flight 77. The flight was carrying three D.C. Public Schools students — Asia Cottom, Bernard Brown and Rodney Dickens — who had been selected to travel to California to participate in an ecology program with researchers from the National Geographic Society.

The children were accompanied by teachers Hilda Taylor, James Debeuneure and Sarah Clark.

“They will forever be part of D.C. Public Schools as we remember this horrific day,” Chancellor Lewis Ferebee said. “We must never forget this experience, what it’s taught us.”

In Montgomery County, Executive Marc Elrich paid tribute to first responders in the county who rushed to the Pentagon on 9/11. “Our fire and police departments joined their peers from around the nation as well as our military by demonstrating their readiness and heroism to come to our aid,” he said in a statement. “We thank them and their families for their service on this day and every day since.”

Retired Arlington County Police Officer Rick Rodriguez, who responded at the Pentagon on 9/11, says one of the things that has stuck with him over the years is how people rushed to help total strangers on that day. “We’ve forgotten how to do that,” he says. “I know neighbors that don’t speak to each other because of political affiliations.”

Dispatcher Richard Spencer remembers something else from the aftermath — the rise of Islamophobia. “There were more calls for Middle Eastern males doing ‘strange things’ that turned out to be absolutely nothing. They they were people who were just going about their lives.”

Spencer also wonders about that first person who called in to report the attack. Is she OK?

“I don’t know who she is, never got her phone number,” Spencer says. “I just hope she got some sort of healing.”

Debbie Truong contributed to this story.