The Globe's photo desk has curated some of the most memorable images from ground zero and the sites of the two other attacks on Sept. 11.
Rescue worker remove fatally injured New York City Fire Department chaplain Rev. Mychal Judge from one of the World Trade Center towers in New York City, early September 11, 2001.Shannon Stapleton/Reuters
Firefighters and emergency personel investigate the scene of a fatal crash involving a United Airlines Boeing 757 with at least 45 passengers Tuesday morning, Sept. 11, 2001 near Shanksville, Pa., Somerset County.David Lloyd/Johnstown Tribune-Democrat/AP
Firefighters battle a blaze at the Pentagon Tuesday, Sept. 11, 2001, after the building took a direct, devasting hit from an aircraft.Heesoon Yim/AP
A group of firefighters walk amid rubble near the base of the destroyed South World Trade Center in New York on September 11, 2001.Peter Morgan/Reuters
People flee lower Manhattan across the Brooklyn Bridge in New York, Tuesday, Sept. 11, 2001, following a terrorist attack on the World Trade Center.Daniel Shanken/AP
The first World Trade Center tower begins to implode in New York, after terrorists flew two airliners into the towers.Det. Greg Semendinger/NYPD/ABC News/AP
A fiery blasts rocks the south tower of the World Trade Center as hijacked United Airlines Flight 175 from Boston crashes into the building September 11, 2001 in New York City.Spencer Platt/Getty Images
In this Tuesday, Sept. 11, 2001 file picture, a person falls headfirst from the north tower of New York's World Trade Center. This photo later became known as "The Falling Man".Richard Drew/AP Photo
Engine 28 firefighter Mike Kehoe, from Staten Island, assists in the evacuation effort in a stairwell of Tower One on Sept. 11, 2001 during the attacks on the World Trade Center towers in New York.John Labriola/AP Photo
This photo shows the point of impact where a plane crashed into the north tower of the World Trade Center in New York City early September 11, 2001.Jeff Christensen/Reuters
Rescue workers sift through the wreckage of the World Trade Center, on Sept. 13, 2001 in New York City.Mario Tama/Getty Images
A man stands in the rubble, and calls out asking if anyone needs help, after the collapse of the first World Trade Center Tower on Sept. 11, 2001, in New York.Doug Kanter/AFP
Rescue workers make their way through the rubble of the World Trade Center on Sept. 11, 2001 in New York after two hijacked planes flew into the landmark skyscrapers.Doug Kanter/AFP
Hijacked United Airlines Flight 175, which departed from Boston en route for Los Angeles, is shown in a flight path for the South Tower of the World Trade Towers on Sept, 11, 2001. The North Tower burns after American Airlines Flight 11 crashed into the tower at 8:45 a.m.Robert Clark/AP/Aurora
The twin towers of the World Trade Center burn behind the Empire State Building in New York in this Sept. 11, 2001 file photo, after hijacked jetliners plunged into both towers.Marty Lederhandler/AP Photo
The rubble of the World Trade Center smoulders following a terrorist attack on Sept. 11, 2001 in New York.Alex Fuchs/AFP
Firefighters work in the rubble of the World Trade Center towers in New York on Sept. 12, 2001. The towers collapsed Tuesday after being struck by two commercial aircrafts in a terrorist attack.Virgil Case/AP Photo
Firefighters walk towards one of the towers at the World Trade Center before it collapsed after a plane hit the building Sept. 11, 2001 in New York City.Jose Jimenez/Primera Hora/Getty Images
Firefighters walk up Chrich Street and away from the remains of the World Trade Center towers in New York, early Sept. 12, 2001.Mike Segar/Reuters
People look out of the burning north tower of the World Trade Center in New York City Sept. 11, 2001. Both towers were hit by planes crashing into the buildings. Shortly after this photo was taken this tower fell.Jeff Christensen/Reuters
Rescue workers survey damage to the World Trade Center on Sept. 11, 2001 in New York.Doug Kanter/AFP
Firefighters raise a flag late in the afternoon on Sept. 11, 2001, in the wreckage of the World Trade Center towers in New York. From left: George Johnson, Dan McWilliams and Billy Eisengrein.Thomas E. Franklin/AP Photo/The Record