What Happened at the Pentagon on September 11, 2001?

Twenty years ago, on September 11, 2001, 19 members of al Qaeda hijacked airplanes in a terrorist attack that took the lives of almost 3,000 people. Among the targets was the Pentagon, the headquarters for the United States Department of Defense.

According to a timeline created by the Wall Street Journal, less than an hour after the first plane hit the World Trade Center, American Airlines Flight 77 crashed into the Pentagon in Arlington, Virginia at 9:37 a.m.

Here’s what you need to know:

United Airlines Flight 77 Crashed into the West Side of the Pentagon

The flight from Dulles Airport circled over downtown Washington, D.C. before crashing into the west side of the building, reported History.com.

Ret. Army Gen. Jack Keane was inside the Pentagon at the time. He was serving as the Army’s vice chief of staff under President George W. Bush.

“I knew it was a terrorist attack,” Keane said in an interview with Fox News. “…I was getting a report from the chief of my operations center — a two-star general — and we were talking about an airplane that had come up I-95 and had come close to Washington, D.C., and then back to the east and went south. He was monitoring the FAA NAS, and this plane.”

Describing the damage, History.com wrote, “Jet fuel from the Boeing 757 caused a devastating inferno that led to the structural collapse of a portion of the giant concrete building.”

Survivors shared stories with the Washington Post of being blown through the air, slipping on the water from sprinklers and even catching on fire. As the outlet reported, the heat from the crash got up to 1,800 degrees.

While the Pentagon filled with smoke, Keane told a two-star general “to get the word to the Army writ large that the Army operation center was operational despite the attack, and that we would maintain that command and control of the Army around the world here,” reported Fox News.

He and his aide then dispersed wet t-shirts, moistened in a bathroom, so people could get out of the building without smoke inhalation, he told the outlet.

“We knew we were at war,” the 78-year-old told Fox News. “The first battle of that war took place in the Pentagon and the World Trade Center. I visited the hospital that night, five different hospitals. We had lots of wounded. Some of them stayed for weeks. I realized that there was a significant amount of heroism that had taken place from the patients in the hospital, as well as from my officers and CEOs and civilians who joined me in the operation center who had been assisting people outside.”

189 People Died in the Pentagon Attack

While Keane told Fox News he lost 85 Army “teammates” in the attack, History.com reported a total of 125 military personnel died in the attack. Along with the 64 airplane passengers who died, 189 people in total died in the Pentagon attack.

Not the only target of the attacks, the al Qaeda suicide hijackers crashed two planes into the twin towers of the World Trade Center and United Airlines Flight 93 crashed in a Pennsylvania field after an on-flight struggle between the passengers and hijackers, according to HIstory.com. The website reported 2,996 people, including the hijackers, died during the attacks.

However, many survivors have battled lingering health issues. As History.com noted, “By 2018, 10,000 people were diagnosed with 9/11-related cancer.”

Reflecting on the attack all these years later, Keane told Fox News he thinks about “the victims that we lost.” He continued telling the outlet, “We are them and also we honor the 9/11 generation who stood up and wanted to go out to protect America, and protect America, they did. They joined the military, they joined the intelligence services, and we’re indebted to them because we’ve never had another attack on foreign soil again, which was the mission.”

READ NEXT: 9/11 20th Anniversary TV Schedule