Many put their own lives on the line to save others during and after the 9/11 terrorist attacks.

The 9/11 attacks resulted in thousands of deaths and unspeakable devastation. But among the people affected were several who demonstrated real-life heroism. Here are a few groups and individuals whose bravery and commitment to helping others was evident on September 11, 2001, and in the days that followed:

American Airlines Flight 11 attendants Betty Ong and Madeline Amy Sweeney helped identify the hijackers

Madeline Amy Sweeney

Madeline Amy Sweeney

American Airlines Flight 11 was the first plane to be hijacked on the morning of September 11, 2001. After terrorists seized control at around 8:15 am, flight attendants Betty Ong and Madeline Amy Sweeney managed to contact the airline. Ong described their situation, including the terrorists' use of a mace-like gas, and Sweeney relayed where the hijackers had been sitting. The two helped authorities understand the kind of threat the country was facing, and the information they shared would prove useful in identifying the hijackers. The flight attendants stayed on their calls until nearly the moment their plane was deliberately flown into the North Tower of the World Trade Center at 8:46 a.m.

Brian Clark rescued a man stuck on the 81st floor of the South Tower

Stanley Praimnath was on the 81st floor of the South Tower when a second plane, United Airlines Flight 175, struck at 9:03 am. Praimnath's location was close enough to the strike point that he could see the plane approaching. Though he miraculously survived, the resulting damage and destruction left him with no discernible way out. Fortunately, Brian Clark, who also worked in the tower, responded to Praimnath's cries for help. With Clark's encouragement, Praimnath managed to jump past debris blocking his way. The two men proceeded to descend from the destroyed upper floors and made it out of the tower. Clark felt Praimnath had helped him survive as well — the group he'd been with when he went to Praimnath's aid had climbed higher to await help, a decision with fatal consequences as the South Tower collapsed at 9:59 am.

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Michael Benfante and John Cerqueira carried a wheelchair-bound woman to safety

Following the attacks, exiting the World Trade Center's towers via elevator wasn't an option. Those evacuating upper floors had to descend in sweltering stairwells that were often filled with smoke. The route was difficult enough for the able-bodied; for wheelchair users it was impossible. When Michael Benfante encountered wheelchair user Tina Hansen on the 68th floor of the North Tower, he and co-worker John Cerqueira carried her in a lightweight emergency chair down multiple flights and through treacherous conditions. Fortunately, all three safely got out of the building.

Patricia Horoho set up a triage area after the Pentagon attacks

Patricia Horoho

Patricia Horoho attends The Woman of the Year USO of Metropolitan New York 43rd Annual Luncheon on April 7, 2009, in New York City.

The Pentagon was the third target of the morning, with American Airlines Flight 77 hitting the building at 9:37 am. Thanks to the efforts of survivors and first responders who bravely entered the fiery crash site, many of the injured made it outside the building. There, a triage area had been set up by Patricia Horoho, an Army nurse who was then a lieutenant colonel. Though Horoho had nothing more than a first aid kit to work with at first, her knowledge and experience in burn care and trauma management helped her oversee the provision of medical treatment. She's credited with caring for 75 people that day, though she noted, "It was an integrated effort by so many people."

Frank De Martini and Pablo Ortiz saved at least 50 lives in the North Tower

Frank De Martini, a construction manager who worked for the Port Authority, and Pablo Ortiz, a Port Authority construction instructor, were inside the North Tower when it was hit. They survived, but instead of seeking safety they began to help people trapped on the tower's 88th and 89th floors. Along with some of their coworkers, the two are thought to have saved at least 50 lives by opening stuck elevator doors, clearing offices, directing people to exits, and otherwise providing a lifeline amid dust, flames and obstructions. They were likely trying to come to the aid of additional people when the North Tower collapsed at 10:28 am.

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Flight 93 passengers Todd Beamer, Mark Bingham, Tom Burnett and Jeremy Glick fought their hijacker

United Airlines Flight 93 was the fourth plane hijacked that morning. Yet the plane's departure from Newark Airport had been delayed until 8:41 am, and the terrorist hijackers didn't seize control until around 9:30. The timing meant that when passengers and crew phoned their loved ones, they learned of the other attacks, and understood the hijackers' intentions for their flight. At least four passengers — Todd Beamer, Mark Bingham, Tom Burnett, and Jeremy Glick — decided to fight back and try to keep the plane they were on from becoming another destructive missile. Burnett told his wife, a flight attendant, "I know we're all going to die. There's three of us who are going to do something about it. I love you, honey." 

On the plane, flight attendant Sandra Bradshaw boiled water, pitchers of which became a weapon alongside cutlery and fire extinguishers. A food cart was launched at the locked cockpit door. The terrorists, realizing the cockpit might be breached, crashed the plane in a field in Shanksville, Pennsylvania, at 10:03 am, killing those on board. These heroic actions kept Flight 93 from reaching its intended target — the terrorists may have planned to strike the White House or the U.S. Capitol Building — and an unknown number of innocent lives were spared.

A boatlift carried 500,000 people to safety

People are evacuated by boat after the attack on the World Trade Center on September 11, 2001

People are evacuated by boat after the attack on the World Trade Center on September 11, 2001.

Manhattan's status as an island can sometimes be forgotten, but the attacks of September 11 highlighted this fact. Though some of those seeking refuge from the area around the World Trade Center were able to travel north, and others crossed the Brooklyn Bridge on foot, thousands had no choice but to head south toward the water. However, instead of finding themselves trapped, they were met by boats ready to provide transportation. Craft had begun to gather even before a call for assistance went out from the Coast Guard. These boats arrived despite the smoke-filled air, which made it difficult to navigate, and understandable fears that another attack might happen at any moment. In the end, more than 100 vessels — from ferries and tugboats to fishing boats and ships that normally offered dinner cruises — took part in the boatlift. Over the course of nine hours, an estimated 500,000 people — many scared, bleeding, or in shock — were carried away to safer locations.

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Sister Cynthia Mahoney provided counseling and blessed remains at Ground Zero for six months

The 9/11 attacks resulted in an immediate loss of 2,753 lives in New York City. This prompted many people to volunteer to help the city in whatever way they could. Some arrived from locations like California, Texas and Virginia. Others were New York City residents, such as Sister Cynthia Mahoney, a nun who'd recently moved there from South Carolina. She had emergency medical training, so quickly jumped into an ambulance to offer her assistance. For six months, she kept returning to Ground Zero, the site of the destroyed World Trade Center, to provide counseling and bless remains. She wrote, "I am grateful I can work in this war zone and be a witness to the heroism every single day... But, when I get home, I do have a hard time. What I've seen has been challenging, but what will stay with me forever is the smell. It is like nothing I have ever experienced." Sister Cynthia died in 2006, having suffered from lung disease she believed was linked to her time volunteering in the toxin-filled air at Ground Zero.

First responders worked day and night searching for remains

Firefighters walk towards one of the towers at the World Trade Center before it collapsed on September 11, 2001.

Firefighters walk towards one of the towers at the World Trade Center before it collapsed on September 11, 2001.

Among the men and women killed on September 11 were many first responders who were at the World Trade Center to assist those trapped and injured by the attacks. The deaths include 23 New York City police officers, 37 Port Authority officers, and 343 members of the New York City fire department. Those who lost their lives in the line of duty were heroes. Yet the first responders who continued to show up and work in the days after the attacks demonstrated their own heroism. After losing colleagues, friends and family members, firefighters, police officers, and others reported for duty at Ground Zero. There, they endured grueling shifts and dangerous conditions as they looked for survivors and searched for remains.