America remembers 9/11 20 years later

Families visit the South Memorial Pool during ceremonies at the World Trade Center site in New York, U.S., September 11, 2011. (Robert Deutsch/Pool via REUTERS) (Robert Deutsch/Pool via REUTERS)

The sun rises behind the Postcards 9/11 memorial by New York architect Masayuki Sono on Staten Island New York on July 30, 2021. Built in 2004, it is a permanent memorial honoring the 274 Staten Island residents killed in the September 11 attacks of 2001 and in the 1993 World Trade Center bombing. Twenty years later, tucked between the buildings and boroughs of New York City, memorials and reminders can be found of a day that left nearly 3,000 people dead  ensuring the city that never sleeps will also never forget. (Photo by KENA BETANCUR/AFP via Getty Images) ( KENA BETANCUR/AFP via Getty Images)

A man walks through the 9/11 Empty Sky memorial at sunrise across from New York's Lower Manhattan and One World Trade Center in Liberty State Park in Jersey City, N.J., on Sept. 11, 2013. (REUTERS/Gary Hershorn/File Photo) (REUTERS/Gary Hershorn)

The Jersey City 9-11 Memorial in New Jersey on July 29, 2021, across from Manhattan. (Photo by KENA BETANCUR/AFP via Getty Images) ( KENA BETANCUR/AFP via Getty Images)

The Hudson Riverfront 9/11 Memorial in Weehawken, N.J., on Aug. 10, 2021. (Photo by KENA BETANCUR/AFP via Getty Images) ( KENA BETANCUR/AFP via Getty Images)

A U.S. honor guard stands next to a metallic model of the World Trade Center during an event to mark the 10th year since the 9/11 attacks on the World Trade Center in the United States, at the U.S. embassy in Kabul, Afghanistan, Sept. 11, 2011. (REUTERS/Stringer/File Photo) (Reuters)

A young boy and his mother looks down into the South Pool during observances on Sept. 11, 2018, held on the 17th year since the September 11, 2001, terror attacks at the annual ceremony at the Ground Zero memorial site. (TIMOTHY A. CLARY/AFP via Getty Images) ( TIMOTHY A. CLARY/AFP via Getty Images)

Visitors gather to pay respects during the Flight 93 National Memorial's annual Luminaria on the eve of 16th Anniversary ceremony of the September 11th terrorist attacks, Sept. 10, 2017, in Shanksville, Pa. United Airlines Flight 93 crashed into a field outside Shanksville with 40 passengers and 4 hijackers aboard on Sep. 11, 2001. (Photo by Jeff Swensen/Getty Images) (Jeff Swensen/Getty Images)

Candlelight vigil for the victims of the World Trade Center terrorist attack at Union Square in New York City on Sept. 13, 2001. (Photo: Evan Agostini/ImageDirect) (Evan Agostini/ImageDirect/Getty Images)

U.S. President George W. Bush listens as White House Chief of Staff Andrew Card informs him of a second plane hitting the World Trade Center while Bush was conducting a reading seminar at the Emma E. Booker Elementary School in Sarasota, Fla., in this Sept. 11, 2001, file photo. (REUTERS/Win McNamee-Files HB) (REUTERS/Win McNamee)

The second tower of the World Trade Center bursts into flames after being hit by a hijacked airplane in New York in this Sept. 11, 2001, file photograph. The Brooklyn bridge is seen in the foreground. (REUTERS/Sara K. Schwittek/Files) (REUTERS/Sara K. Schwittek)

Walking to Brooklyn during 9/11 attacks. (Photo by Robert Essel NYC/CORBIS/Corbis via Getty Images) ( Robert Essel NYC/CORBIS/Corbis via Getty Images)

Standing atop rubble with retired New York City firefighter Bob Beckwith, President George W. Bush rallies firefighters and rescue workers during an impromptu speech at the site of the collapsed World Trade Center in New York City, Sept. 14, 2001. (Image courtesy National Archives. Photo via Smith Collection/Gado/Getty Images.) ( Smith Collection/Gado/Getty Images)

An unidentified New York City firefighter walks away from Ground Zero after the collapse of the Twin Towers September 11, 2001 in New York City. (Photo by Anthony Correia/Getty Images) ( Anthony Correia/Getty Images)

Aerial view of Ground Zero at the World Trade Center in New York on Sept. 26, 2001. Fifteen days after the attack, hundreds of rescue workers continued to sift through the ruins of the World Trade Center in a desperate search for survivors and, failing that, for the remains of those killed. (REUTERS/U.S. Customs Service-Handout) (REUTERS/U.S. Customs Service-Handout)

People walk in the street in the area where the World Trade Center buildings collapsed Sept. 11, 2001, after two airplanes slammed into the twin towers in a terrorist attack. (Photo by Mario Tama/Getty Images) (Mario Tama/Getty Images)

The damaged area of the Pentagon building, where a commercial jetliner slammed into it on Sept. 11, 2001, is seen in the early morning at sunrise with the U.S. Capitol Building in the background, Sept. 16, 2001. Both the Pentagon and the World Trade Center buildings in New York City were attacked by hijacked commercial airliners. (Reuters)

President George W. Bush and Secretary of Defense Donald Rumsfeld survey the damage at the Pentagon building Sept. 12, 2001, in Arlington, Va, a day after the Sept. 11, 2001, terrorist attacks in Washington, D.C., and New York. (Photo by David Hume Kennerly/Getty Images) ( David Hume Kennerly/Getty Images)

An unidentified motorist watches smoke billow from the Pentagon in Washington, D.C., Sept. 11, 2001, after an airplane crashed into it. (LUKE FRAZZA/AFP via Getty Images) (LUKE FRAZZA/AFP via Getty Images)

Smoke comes out from the Southwest E-ring of the Pentagon building Sept. 11, 2001, in Arlington, Va., after a plane crashed into the building and set off a huge explosion. (Photo by Alex Wong/Getty Images) (Alex Wong/Getty Images)

President Obama, first lady Michelle Obama, former President George W. Bush and former first lady Laura Bush look out at the North Pool of the 9/11 Memorial during the 10th-year ceremonies of the Sept. 11, 2001, terrorist attacks at the World Trade Center site, Sept. 11, 2011, in New York City. (Photo by Kristoffer Tripplaar-Pool/Getty Images) (Kristoffer Tripplaar-Pool/Getty Images)

A man walks in the street near the World Trade Center towers in New York City, early Sept. 11, 2001. Both towers were hit by planes that crashed into the buildings, which collapsed shortly after. (REUTERS/Shannon Stapleton) (Reuters)

The last steel girder left standing at the World Trade Center, covered with black cloth and an American flag, is carried from the World Trade Center site in New York on May 30, 2002, marking the completion of recovery work from the Sept. 11, 2001, attacks on the twin towers.  New York marked the end of the mammoth recovery of human remains and disposal of the ruins of the World Trade Center with a brief ceremony, nearly nine months after two hijacked planes slammed into the twin towers, destroying them and killing 2,823 people. (Reuters)

Firefighters make their way over the ruins through clouds of smoke as work continues at ground zero in New York, one month after the attacks on the World Trade Center, Oct. 11, 2001. (REUTERS/Stan Honda/POOL ME/HK) (REUTERS/Stan Honda/POOL )

People gather as President Trump speaks on Sept. 11, 2018, at the site of a new memorial in Shanksville, Pa., where Flight 93 crashed during the September 11 attacks, as somber ceremonies take place at Ground Zero in New York and at the Pentagon. (NICHOLAS KAMM/AFP via Getty Images) (NICHOLAS KAMM/AFP via Getty Images)