A fiery blasts rocks the south tower of the World Trade Center as the hijacked United Airlines Flight 175 from Boston crashes into the building September 11, 2001 in New York City. (Photo by Spencer Platt/Getty Images)

Smoke Pours From The World Trade Center After Being Hit By Two Planes September 11, 2001 In New York City. (Photo By Craig Allen/Getty Images)

Retired Fire Chief Joseph Curry barks orders to rescue teams as they clear through debris that was once the World Trade Center September 14, 2001 in New York City. (U.S. Navy Photo by Jim Watson/Getty Images)

A New York City fireman calls for 10 more rescue workers to make their way into the rubble of the World Trade Center September 14, 2001 days after the September 11, 2001 terrorist attack. (U.S. Navy Photo by Jim Watson/Getty Images)

Policemen and firemen run away from the huge dust cloud caused as the World Trade Center’s Tower One collapses after terrorists crashed two hijacked planes into the twin towers, September 11, 2001 in New York City. (Photo by Jose Jimenez/Primera Hora/Getty Images)

New York City firefighters work at the World Trade Center after two hijacked planes crashed into the Twin Towers September 11, 2001 in New York. (Photo by Ron Agam/Getty Images)

394277 14: New York City firefighters take a rest at the World Trade Center after two hijacked planes crashed into the Twin Towers September 11, 2001 in New York. (Photo by Ron Agam/Getty Images)

A search dog sleeps behind a New York firefighter at the scene of the World Trade Center collapse September 15, 2001 in New York City. (Photo by Preston Keres/US Navy/Getty Images)

Streets of lower Manhattan with fireman, police, and rescue crews after the collapse of the World Trade Center after being hit by two airplanes on September 11, 2001. photo by Gabe Palacio/ImageDirect

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. The World Trade Center’s Twin Towers and the Pentagon were attacked by terrorists using commercial airliners as missiles. (Photo by Anthony Correia/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. The World Trade Center’s Twin Towers and the Pentagon were attacked by terrorists using commercial airliners as missiles. (Photo by Anthony Correia/Getty Images)

People evacuate the area around the World Trade Center after it was hit by two planes September 11, 2001 in New York City. (Photo by Mario Tama/Getty Images)

A woman reacts in terror as she looks up to see the World Trade Center go up in flames September 11, 2001 in New York City after two airplanes slammed into the twin towers in an alleged terrorist attack. (Photo by Spencer Platt/Getty Images)

U.S. President George W. Bush (C) makes a telephone call as White House Director Of Communications Dan Bartlett points to video footage of the terrorist attack on the World Trade Center from Emma Booker Elementary School September 11, 2001 in Sarasota, Florida. (Photo by Eric Draper/White House/Getty Images)

Visitors browse newspaper front pages with the story of the 9/11 terror attacks at the 9/11 Gallery of the Newseum on September 9, 2016 in Washington, DC. The nation will mark the 15th anniversary of the terror attacks on Sunday. (Photo by Alex Wong/Getty Images)

People walk by the Oculus located at the World Trade Center during a morning commemoration ceremony for the victims of the terrorist attacks seventeen years after the day on September 11, 2018 in New York City. (Photo by Spencer Platt/Getty Images)

A worker holds an umbrella while adjusting beams of the Tribute in Lights ahead of the tenth anniversary of the September 11 terrorist attacks on September 7, 2011 in New York City. The Tribute in Light is comprised of 88 7000 watt searchlights that beam into the sky near the site of the World Trade Center in remembrance of the September 11 attacks. (Photo by Justin Sullivan/Getty Images)

U.S. President George W. Bush holds an American flag during a Memorial Service at the Pentagon October 11, 2001 in Arlington, Virginia. (Photo by Mark Wilson/Getty Images)

Visitors gather to pay respects during the Flight 93 National MemorialÕs annual Luminaria on the eve of 16th Anniversary ceremony of the September 11th terrorist attacks, September 10, 2017 in Shanksville, PA. (Photo by Jeff Swensen/Getty Images)

New York City firefighters pause outside of Engine Company 10 and Ladder Company 10 across from One World Trade Center, the Freedom Tower, in lower Manhattan during commemoration ceremonies for the September 11, 2001 terror attacks on September 11, 2020 in New York City.  (Photo by Spencer Platt/Getty Images)

Allan Swearington joins others at the 9/11 memorial plaza on the first day that it has reopened after closing for three months due to the coronavirus on on July 04, 2020 in New York City. (Photo by Spencer Platt/Getty Images)

People write messages on white ribbons that hang from the fence at St. Paul’s Chapel across from the World Trade Center site on September 10, 2011 in New York City.  (Photo by Justin Sullivan/Getty Images)

One World Trade Center, the Freedom Tower, stands in lower Manhattan during commemoration ceremonies for the September 11, 2001 terror attacks on September 11, 2020 in New York City. Hundreds of people have gathered for the 19th anniversary of the event at Ground Zero to remember the nearly 3,000 who were killed on that day.  (Photo by Spencer Platt/Getty Images)

A woman touches a carnation left on a name inscribed into the North Pool during 9/11 Memorial ceremonies marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York on September 11, 2013 in New York City.  (Photo by Adrees Latif-Pool/Getty Images)

Democratic presidential nominee Joe Biden meets with an attendee at a 9/11 memorial service at the National September 11 Memorial and Museum on September 11, 2020 in New York City. The ceremony to remember those who were killed in the terror attacks 19 years ago will be altered this year in order to adhere to safety precautions around COVID-19 transmission. (Photo by Amr Alfiky – Pool/Getty Images)

President Donald J. Trump and First Lady Melania Trump lay a wreath during a ceremony at the Flight 93 National Memorial commemorating the 19th anniversary of the crash of Flight 93 and the September 11th terrorist attacks on September 11, 2020 in Shanksville, Pennsylvania. (Photo by Jeff Swensen/Getty Images)

Smoke from various wildfires burning across Northern California mixes with the marine layer, blanketing the San Francisco skyline in darkness and an orange glow, seen from Treasure Island on September 9, 2020 in San Francisco, California. Over 2 million acres have burned this year as wildfires continue to burn across the state. (Photo by Philip Pacheco/Getty Images)