How many people died in the 9/11 attacks?

Nearly 3,000 people were killed after four planes were hijacked by attackers from the Al Qaeda terrorist group.

Two planes flew into the World Trade Center’s Twin Towers in New York. One plane was flown into the Pentagon. Another aircraft crashed into an open field in Pennsylvania after passengers fought back — the only plane that didn’t reach its intended destination.

The painstaking process of positively identifying the remains of those killed at the World Trade Center continues more than two decades after the attack. With advancements in DNA technology, remains of two victims were ID’d just last week.

In addition to the toll that day, the World Trade Center attack exposed hundreds of thousands of people in lower Manhattan to toxic air and debris, and hundreds have since died from post-9/11 related  illnesses. The exact number is unknown, but firefighter union leaders say 341 FDNY members have died of illnesses related 9/11, CBS New York reports.

What time did the 9/11 attacks happen?

The first plane, American Airlines Flight 11, crashed into the World Trade Center’s North Tower at 8:46 a.m. ET, killing everyone aboard and trapping people in upper floors of the tower. At 9:03 a.m., the second plane, United Airlines Flight 175, hit the World Trade Center’s South Tower. Both towers soon collapsed — the South Tower just before 10 a.m., then the North Tower a half-hour later.

American Airlines Flight 77 hit the Pentagon at 9:37 a.m.

Then at 10:03 a.m., United Flight 93 crashed into a field in Shanksville, Pennsylvania.

What happened at the Pentagon and in Shanksville, Pennsylvania?

When American Airlines Flight 77 crashed into the southwest corner of the Pentagon, 184 people were killed — 64 who were on the plane and 125 people in the building.

Sean Boger was one of the few people at the Pentagon who saw the plane coming in so low it took down a street light.

“I just looked up and, you know, a plane was flying directly at us,” he told CBS News in 2021. He said it was just 10 to 15 seconds before the plane hit the building.

Boger was in the control tower for the Pentagon’s helipad when he saw the plane, which he said sounded “like someone sawing medal” when it hit.

“I just couldn’t believe something that big could be flying that low and flying directly at us,” he said.

A memorial observance is also being held at the Pentagon Monday morning.

Less than 30 minutes later, United Airlines Flight 93 — the fourth plane downed in the terror attack — crashed into a field in Pennsylvania. That plane had been hijacked and was heading to Washington, D.C., but never made it after passengers and crew took action.

They were pushed to the back of the plane by hijackers, then took a vote and decided to try to regain control of the aircraft, according to the Friends of Flight 93 National Memorial. A struggle ensued, and the plane eventually crashed in an open area.

“Countless lives were spared thanks to their heroic actions, but all on board Flight 93 were lost,” the memorial says.

A memorial observance is also being held there Monday morning.