A look back at 9/11 tributes through the years

Pedestrians in lower Manhattan watch smoke billow from New York's World Trade Center on Tuesday, Sept. 11, 2001. (AP Photo/Amy Sancetta)

Thick smoke billows into the sky from the area behind the Statue of Liberty, lower left, where the World Trade Center was, on Tuesday, Sept. 11, 2001. (AP Photo/Daniel Hulshizer)

Smoke billows through buildings in Manhattan as seen from Brooklyn after the collapse of New York's World Trade Center, Tuesday, Sept. 11, 2001. (AP Photo/Kathy Willens)

Two women hold each other as they watch the World Trade Center burn in New York Tuesday, Sept. 11, 2001. (AP Photo/Ernesto Mora)

Pedestrians on Pierrepont Place in the Brooklyn borough of New York, watch as smoke billows from the remains of the World Trade Center in New York, Sept. 11, 2001. (AP Photo/Lawrence Jackson)

Deputy chief of the Army Reserve, Col. Malcolm Bruce Westcott, comforts Pentagon employee Racquel Kelley while giving her medical aid outside the Pentagon in Washington on Tuesday, Sept. 11, 2001. (AP Photo/Will Morris)

A firefighter moves through piles of debris at the site of the World Trade Center in New York, Tuesday, Sept. 11, 2001. (AP Photo/Graham Morrison)

People walk over New York's Brooklyn Bridge from Manhattan to Brooklyn following the collapse of both World Trade Center towers on Sept. 11, 2001. (AP Photo/Mark Lennihan)

Fire and smoke billows from the north tower of New York's World Trade Center on Tuesday, Sept. 11, 2001. (AP Photo/David Karp)

Flames and smoke pour from a building at the Pentagon in Washington on Tuesday, Sept. 11, 2001. (AP Photo/Will Morris)

A fireman screams in pain as he is rescued shortly after both towers of New York's World Trade Center collapsed following a terrorist attack, Tuesday, Sept. 11, 2001. (Robert Mecea/Newsday via AP)

People cover their faces as they escape the collapse of New York's World Trade Center on Sept. 11, 2001. (AP Photo/Suzanne Plunkett)

The remains of the World Trade Center stands amid the debris in New York, Tuesday, Sept. 11, 2001. (AP Photo/Alexandre Fuchs)

Pedestrians flee the area of New York's World Trade Center in lower Manhattan on Tuesday, Sept. 11, 2001. (AP Photo/Amy Sancetta)

Harry Shasho sweeps up before being evacuated from his vitamin store after the collapse of New York's World Trade Center on Tuesday, Sept. 11, 2001. (AP Photo/Suzanne Plunkett)

People flee the falling South Tower of the World Trade Center on Tuesday, Sept. 11, 2001. (AP Photo/Amy Sancetta)

People flee the scene near New York's World Trade Center Tuesday, Sept. 11, 2001. (AP Photo/Diane Bondareff)

A person falls from the north tower of New York's World Trade Center as another clings to the outside, left, while smoke and fire billow from the building, Tuesday Sept. 11, 2001. (AP Photo/Richard Drew)

Smoke billows from one of the towers of the World Trade Center as flames and debris explode from the second tower, Tuesday, Sept. 11, 2001. (AP Photo/Chao Soi Cheong)

Firefighters work beneath the destroyed mullions, the vertical struts, of the World Trade Center in New York on Tuesday, Sept. 11, 2001. (AP Photo/Mark Lennihan)

Tribute in Light, two vertical columns of light representing the fallen towers of the World Trade Center shine against the lower Manhattan skyline on the 19th anniversary of the September 11, 2001 terror attacks, seen from Jersey City, N.J., Friday, Sept. 11, 2020. (AP Photo/Stefan Jeremiah))

A U.S. flag is unfurled at sunrise at the Pentagon on the 17th anniversary of the September 11th attacks, Tuesday, Sept. 11, 2018. (AP Photo/Pablo Martinez Monsivais)

This is a flag left at the Flight 93 National Memorial in Shanksville, Pa, Friday, Sept. 11, 2015, as the nation marks the 14th anniversary of the Sept. 11 attacks. (AP Photo/Gene J. Puskar)

Soldiers with the U.S. Army's 25th Infantry Division, 3rd Brigade Combat Team, 2nd Battalion 27th Infantry Regiment based in Schofield Barracks, Hawaii, hold a ceremony commemorating the tenth anniversary of the 9/11 attacks and soldiers the unit has lost since then in the wars in Iraq and Afghanistan Sunday, Sept. 11, 2011 at Forward Operating Base Bostick in Kunar province, Afghanistan. (AP Photo/David Goldman)

A woman places flowers in the inscribed names along the edge of the North Pool during memorial observances on the 13th anniversary of the Sept. 11, 2001 terror attacks on the World Trade Center in New York, Thursday, Sept. 11, 2014. (AP Photo/Justin Lane, Pool)

Mourners hug beside the names of the deceased Jesus Sanchez and Marianne MacFarlane at the National September 11 Memorial and Museum, Friday, Sept. 11, 2020, in New York. Americans commemorated 9/11 with tributes that have been altered by coronavirus precautions and woven into the presidential campaign. (AP Photo/John Minchillo)

Firefighters salute in front of FDNY Ladder 10 Engine 10 near the 9/11 Memorial on Friday, Sept. 11, 2020, in New York. Americans are commemorating 9/11 with tributes that have been altered by coronavirus precautions and woven into the presidential campaign, drawing President Donald Trump and Democratic challenger Joe Biden to pay respects at the same memorial without crossing paths.(AP Photo/Kevin Hagen)

A boy waves to passing motorists to commemorate the anniversary of the Sept. 11 terrorist attacks from an overpass on Interstate 35 Wednesday, Sept. 11, 2019, near Melvern, Kan. Area residents began manning the bridge with flags and waving to motorists on the anniversary in 2002 and have done it ever since. (AP Photo/Charlie Riedel)

A person stops to read names in New Jersey's memorial to the 749 people from the state lost during the Sept. 11 terrorist attacks on the World Trade Center, as One World Trade Center, now up to 104 floors, looms in the distance across the Hudson River, Tuesday, Sept. 11, 2012 in Jersey City, N.J. Americans paused again Tuesday to mark the 11th anniversary of the Sept. 11, 2001, terror attacks with familiar ceremonies, but also a sense that it's time to move forward after a decade of remembrance. (AP Photo/Mel Evans)

A woman reaches out to touch rose on one of the benches of the Pentagon Memorial at the at the Pentagon, Thursday, Sept. 11, 2014. President Barack Obama will attend the wreath laying later this morning to to mark the 13th anniversary of the 9/11 attacks. (AP Photo/Pablo Martinez Monsivais)

Sophia Demos sits with her daughter, Evniki Tsokanis, 4, among a sea of American flags during a memorial Thursday, Sept. 11, 2014, in Matthews, N.C., on the 13th anniversary of the Sept. 11, terrorist attacks. The 2,997 American flags are displayed for each person lost on Sept. 11, 2001. (AP Photo/Chuck Burton)

The Tribute in Light rises above the lower Manhattan skyline, Wednesday, Sept. 11, 2019, as taken from Bayonne, N.J. (AP Photo/Eduardo Munoz Alvarez)

A charred piece of limestone salvaged from the terror attack where American Airlines Flight 77 hit the Pentagon is inscribed with the words "September 11, 2001" is seen on the fifth anniversary of the attack Monday, Sept. 11, 2006, in Washington. Behind the stone lies a time capsule to commemorate victims of the attack. (AP Photo/Charles Dharapak)

Mourners place flowers and pictures in the name cut-out of Kyung Hee (Casey) Cho at the National September 11 Memorial and Museum, Friday, Sept. 11, 2020, in New York. Americans are commemorating 9/11 as a new national crisis in the form of the coronavirus pandemic reconfigures and divides anniversary ceremonies and a presidential campaign carves a path through the observances. (AP Photo/John Minchillo)

Crowds gather on the 18th anniversary of the attacks of Sept. 11, 2001 at the National September 11 Memorial, Wednesday, Sept. 11, 2019 in New York. (AP Photo/Jacqueline Larma)

Red roses are placed next to names names of victims of the Sept. 11, 2001 terrorist attacks on the U.S. at a memorial site during a ceremony marking the 12th anniversary of 9/11 outside Jerusalem, Wednesday, Sept. 11, 2013. (AP Photo/Bernat Armangue)

New York firefighters stand behind a surfboard, below, displaying the names and photos of firefighters killed during the Sept. 11, 2001 attacks, during a Sept. 11 remembrance ceremony Wednesday, Sept. 11, 2013, on the flight deck of the USS Midway aircraft carrier in San Diego. About fifteen New York firefighters, many of whom responded to the World Trade Center on Sept. 11, 2001, were honored Wednesday in San Diego, as they took turns reading the names of fellow firefighters who lost their lives in the attacks. (AP Photo/Gregory Bull)

Chrissy Bortz of Latrobe, Pa., pays her respects at the Wall of Names at the Flight 93 National Memorial in Shanksville, Pa. after a Service of Remembrance Tuesday, Sept. 11, 2018, as the nation marks the 17th anniversary of the Sept. 11, 2001 attacks. The Wall of Names honor the 40 people killed in the crash of Flight 93. (AP Photo/Gene J. Puskar)

Navy Quartermaster Matthew Konchan of Johnstown, Pa., stands in a field of black-eyed Susan as he waits to participate in a wreath laying with Secretary of the Interior Sally Jewell during a memorial service at the Flight 93 National Memorial on Wednesday, Sept. 11, 2013 in Shanksville. (AP Photo/Gene J. Puskar)

A runner stops to take a photograph of names on the "Empty Sky" memorial to New Jersey's victims of the Sept. 11, 2001 terrorist attacks, early Friday, Sept. 11, 2015, in Jersey City, N.J. (AP Photo/Mel Evans)

A couple embraces as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

People gather during a ceremony marking the 10th anniversary of the attacks on the World Trade Center Sunday, Sept. 11, 2011, outside the World Trade Center site in New York. (AP Photo/Oded Balilty)

The Tribute in Light rises above the New York skyline and One World Trade Center, left, Friday, Sept. 11, 2015, in a view from Bayonne, N.J. It was the 14th anniversary of the Sept. 11 terror attacks on Friday. (AP Photo/Mark Lennihan)

People look at luminaires placed on the steps of the replica of the Parthenon in Nashville, Tenn., Wednesday, Sept. 11, 2002. On each bag is the name of a victim of the Sept. 11, 2001 terrorist attacks. (AP Photo/Mark Humphrey)

Friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012.(AP Photo/Jason DeCrow)

Robert and Briana Genetti, right, of Lincoln, Neb., huddle under a United States flag as they participate in a ceremony held to commemorate the one year anniversary of the attacks of Sept. 11, held at Lincoln's Pioneers Park, Wednesday, Sept 11, 2002. (AP Photo/Nati Harnik)

Petty Officer 2nd Class Jeremy Nash pays his respects Wednesday, Sept. 11 2002, at Marion Square in Charleston, S.C., to those killed a year ago. A flag was placed in the park as a symbol of every life lost during the terrorist attacks. (AP Photo/Paula Illingworth)

Approximately 3,000 pairs of shoes are arranged as a memorial to the victims of the attacks of Sept. 11, 2001, on the town common in Stoneham, Mass., Wednesday, Sept. 11, 2002. (AP Photo/Robert E. Klein)

A visitor takes a picture of the boulder that marks the crash site of United Flight 93 at the Wall of Names after a Service of Remembrance at the Flight 93 National Memorial in Shanksville, Pa, Friday, Sept. 11, 2015. Hundreds of victims' relatives gathered for what has become a tradition of tolling bells, moments of silence and the reading of the names of the nearly 3,000 people killed in the terror strikes at the World Trade Center, the Pentagon and a field near Shanksville, Pennsylvania. (AP Photo/Gene J. Puskar)

The "Tribute in Light" marks the September 11 Anniversary in New York taken from Bayonne, N.J. on Tuesday, Sept. 11, 2007. (AP Photo/Tim Larsen)

Several hundred miniature American flags were placed on the lawn of the Phi Delta Theta fraternity house on the campus of the University of Mississippi to commemorate the 14th anniversary of the Sept. 11 terror attacks on Friday, Sept. 11, 2015, in Oxford, Miss. (AP Photo/Rogelio V. Solis)

Celeste Pocher embraces her daughter after finding her brother in law's name, John Pocher at the north pool at the National September 11 Memorial during a ceremony marking the 10th anniversary of the attacks at the World Trade Center, Sunday, Sept. 11, 2011 in New York. (AP Photo/Mary Altaffer)

Former first lady Laura Bush, from left, former President George W. Bush, first lady Michelle Obama and President Barack Obama hold hands to their hearts during the national anthem as friends and relatives of the victims of 9/11 gather for a ceremony marking the 10th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site, Sunday, Sept. 11, 2011, in New York. (AP Photo/Jason DeCrow)

The Tribute in Light shines above Lower Manhattan, marking the 10th anniversary of the attacks at the World Trade Center site, Sunday, Sept. 11, 2011, in New York. (AP Photo/Matt Rourke)

President Barack Obama lays a wreath at the Pentagon, Wednesday, Sept. 11, 2013, during a ceremony marking the 12th anniversary of the worst terror attack on the US. The Pentagon was struck by one of the hijacked plane. (AP Photo/Manuel Balce Ceneta)

President Barack Obama, first lady Michelle Obama, and others, pause on the South Lawn of the White House in Washington, Friday, Sept. 11, 2015, as they observe a moment of silence to mark the 14th anniversary of the 9/11 attacks. (AP Photo/Andrew Harnik)

Iraq and Afghanistan war veteran U.S. Army Chaplain Capt. Kevin Peek, looks over his speech before he speaks during a ceremony to commemorate the 11th anniversary of the Sept. 11 terrorist attacks on the campus of Georgia Tech Tuesday, Sept. 11, 2012, in Atlanta. (AP Photo/David Goldman)

Retired New York City firefighter Joseph McCormick visits the South Pool prior to a ceremony at the World Trade Center site in New York on Friday, Sept. 11, 2015. With a moment of silence and somber reading of names, victims' relatives began marking the 14th anniversary of Sept. 11 in a subdued gathering Friday at ground zero. (AP Photo/Bryan R. Smith)

New York City Fire Dept. Capt.Tom Engel, of Ladder 133, in the Queens borough of New York, plays taps during the observance at the World Trade Center Memorial held on the eleventh anniversary of the attacks on the World Trade Center, Tuesday, Sept. 11, 2012 in New York. (AP Photo/Mary Altaffer, Pool)

As seen from the Pentagon Memorial, a U.S. flag is draped on the side of the Pentagon where the attack took place on September 11th in 2001, on the 14th anniversary of the attack, Friday Sept. 11, 2015, in Washington. (AP Photo/Jacquelyn Martin)

Yachiyo Kuge, the mother of Toshiya Kuge, of Japan, who was a passenger on Flight 93, carries a lantern to place at her daughter's name on the Wall of Names at the Flight 93 National Memorial in Shanksville, Pa., Thursday, Sept 10, 2015. The new $26 million visitors’ complex is expected to draw a larger crowd than normal for the 14th anniversary observance at the Flight 93 National Memorial. (AP Photo/Gene J. Puskar)

Rick Sarmiento, center, embraces Karen Bingham, left, and Nancy Root, right, during a visit to the Flight 93 National Memorial on Wednesday, Sept. 10, 2014, Shanksville, Pa. Karen Bingham's son Mark Bingham was a passenger on Flight 93, as was Nancy Root's cousin Lorraine G. Bay. The memorial marks the spot where United Airlines Flight 93 crashed 13 years ago in a reclaimed strip mine some 75 miles southeast of Pittsburgh after passengers fought back against hijackers. (AP Photo/Gene J. Puskar)

Army Sgt. Edwin Morales prays during a ceremony at the World Trade Center site in New York on Friday, Sept. 11, 2015. With a moment of silence and somber reading of names, victims' relatives began marking the 14th anniversary of Sept. 11 in a subdued gathering Friday at ground zero.(AP Photo/Bryan R. Smith)

Christine Box, sister of Firefighter Gary Box, remembers her brother with her daughter Nikki Silva, during a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/The Daily News, Todd Maisel, Pool)

John Pristas, a firefighter for the Cranberry Township Volunteer Fire Company, blows "Taps" on a trumpet during a ceremony in marking the anniversary of the terrorist attacks of Sept. 11, 2001, at their 9/11 Memorial in front of the station on Monday, Sept. 11, 2017, in Cranberry, Pa. Butler county. (AP Photo/Keith Srakocic)

President Donald Trump and first lady Melania Trump, stand along the September 11th Flight 93 Memorial, Tuesday, Sept. 11, 2018, in Shanksville, Pa., escorted by (AP Photo/Evan Vucci)

Retired New York firefighter Bruce Stanley carries a photograph of fellow firefighter Leon Smith Jr. during a ceremony at the World Trade Center marking the 17th anniversary of the terrorist attacks on the United States. Tuesday, Sept. 11, 2018, in New York. Smith was one of 343 members of the fire department who were killed on Sept. 11, 2001. (AP Photo/Mark Lennihan)

A woman looks at the north pool of the September 11 Memorial, Monday, Sept. 9, 2019 in New York. Wednesday marks the 18th anniversary of the attacks of Sept. 11, 2001. (AP Photo/Mark Lennihan)

Names of the 40 passengers and crew of Flight 93 are read followed by the ringing of two bells during a memorial service help at the Flight 93 National Memorial in Shanksville, Pa., Friday, Sept. 11, 2020.(AP Photo/Gene J. Puskar)

The Tribute in Light rises behind the Brooklyn Bridge and buildings adjacent to the World Trade Center complex, Wednesday, Sept. 10, 2014 in New York. The tribute, an art installation of 88 searchlights aiming skyward in two columns, is a remembrance of the Sept. 11, 2001, attacks. (AP Photo/Mark Lennihan)

Mourners gather at the north pool adorned with flowers and flags during ceremonies to commemorate the 20th anniversary of the Sept. 11 terrorist attacks, Saturday, Sept. 11, 2021, at the National September 11 Memorial & Museum in New York. (AP Photo/John Minchillo)

President Joe Biden and first lady Jill Biden participate in a wreath ceremony on the 20th anniversary of the terrorist attacks at the Pentagon in Washington, Saturday, Sept. 11, 2021, standing at the National 9/11 Pentagon Memorial site, which commemorates the lives lost at the Pentagon and onboard American Airlines Flight 77. With the President, not shown, are Vice President Kamala Harris and her husband Douglas Emhoff, Secretary of Defense Lloyd Austin and Joint Chiefs Chairman Gen. Mark Milley and his wife Hollyanne Milley. (AP Photo/Alex Brandon)

The annual “Tribute in Light” is illuminated on the 20th anniversary of the Sept. 11 attacks on Saturday, Sept. 11, 2021, in New York. (AP Photo/Brittainy Newman)

The annual "Tribute in Light" is illuminated above Lower Manhattan on the 20th anniversary of the Sept. 11 terror attacks on Sept. 11, 2021, in New York. (AP Photo/Brittainy Newman)

New York Mets fans wear jerseys to remember the 20th anniversary of the 9/11 terrorist attacks before a baseball game against the New York Yankees on Saturday, Sept. 11, 2021, in New York. (AP Photo/Adam Hunger)