PHOTOS: How the nation is remembering Sept. 11 on 20th anniversary

More than 200 Arlington first responders paid tribute to fallen first responders by laying roses on charred piece of steel from ground zero in NY. Many of them were at the Pentagon that day. (WTOP/Gigi Barnett)

Up to 700 volunteers worked in shifts assembling 200,000 meals destined for area foodbanks.

Fmr. Battalion Chief Dale Smith placing rose on charred steel from ground zero. WTOP/Gigi Barnett

Up to 700 volunteers worked in shifts assembling 200,000 meals destined for area foodbanks. (WTOP/Dick Uliano)

President Joe Biden and first lady Jill Biden walk to board Air Force One at Pennsylvania Army Air National Guard Base in Johnstown, Pa., Saturday, Sept. 11, 2021. The Bidens are en route to Washington after visiting the Flight 93 National Memorial in Shanksville, Pa., to commemorate the 20th anniversary of the Sept. 11, 2001, terrorist attacks. (AP Photo/Evan Vucci)

A sky diver lands on the field with an oversized United States flag prior to the start of an NCAA college football game between Northwestern and Indiana State in Evanston, Ill, Saturday, Sept. 11, 2021. (AP Photo/Matt Marton)

Former President Donald Trump visits the Engine Co. 8 firehouse where he praised first responders’ bravery while criticizing President Joe Biden over the pullout from Afghanistan, Saturday Sept. 11, 2021, in New York. (AP Photo/Jill Colvin)

A red, white and blue ribbon, to mark Sept. 11, 2001 anniversary, marks the field near the Texas A&M bench before an NCAA college football game against Colorado, Saturday, Sept. 11, 2021, in Denver. (AP Photo/David Zalubowski)

President Joe Biden speaks to people as he visits the Shanksville Volunteer Fire Department in Shanksville, Pa., Saturday, Sept. 11, 2021. Biden stopped by after visiting the nearby Flight 93 National Memorial to commemorate the 20th anniversary of the Sept. 11, 2001, terrorist attacks. (AP Photo/Evan Vucci)

Mourners stand at the rim of the north pool with the white World Trade Center Oculus in the background after the conclusion of 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)

Mayor Muriel Bowser and the Council of the District of Columbia joined first responders and officers in commemorating the 20th anniversary of 9/11. (Courtesy Twitter/DC Homeland Security & Emergency Management)

Mayor Muriel Bowser and the Council of the District of Columbia joined first responders and officers in commemorating the 20th anniversary of 9/11. (Courtesy Twitter/DC Homeland Security & Emergency Management)

A trumpeter plays “Taps” beside the north pool at the conclusion of ceremonies to commemorate the 20th anniversary of the Sept. 11, 2001 terrorist attacks, Saturday, Sept. 11, 2021, at the National September 11 Memorial & Museum in New York. (AP Photo/John Minchillo)

People tie ribbons to the fence at St. Paul’s Chapel near the National September 11 Memorial & Museum during a ceremony marking the 20th anniversary of the 9/11 terrorist attacks, Saturday, Sept. 11, 2021, in New York. (AP Photo/Matt Rourke)

Virginia Governor Ralph Northam, hand over heart, at a ceremony remembering the 3,000 lost and the first responders who entered the Pentagon 20 years ago. (Courtesy Twitter/Office of Governor Ralph Northam)

Former President George W. Bush, right, wipes his eyes next to former first lady Laura Bush, after he spoke at a memorial for the passengers and crew of United Flight 93, Saturday, Sept. 11, 2021, in Shanksville, Pa., on the 20th anniversary of the Sept. 11, 2001, attacks. (AP Photo/Jacquelyn Martin)

Transportation Security Administration (TSA) employees and guests take part in a moment of silence during an event to commemorate the 20th anniversary of the Sept. 11, 2001, terrorist attacks, Saturday, Sept. 11, 2021, in Springfield, Va. (AP Photo/Luis M. Alvarez)

President Joe Biden and first lady Jill Biden lay a wreath at the Wall of Names during a visit to the Flight 93 National Memorial in Shanksville, Pa., Saturday, Sept. 11, 2021. The Bidens visited to commemorate the 20th anniversary of the Sept. 11, 2001, terrorist attacks. (AP Photo/Evan Vucci)

A shadow of a rose is projected onto a flag held by Germano Rivera by the north pool 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)

On the 20th anniversary of Sept. 11, an Alexandria fire station hosts Sen. Tim Kaine and Terry McAuliffe for a ceremony remembering that tragic day. (WTOP/Gigi Barnett)

On the 20th anniversary of Sept. 11, an Alexandria fire station hosts Sen. Tim Kaine and Terry McAuliffe for a ceremony remembering that tragic day. (WTOP/Gigi Barnett)

Vice President Kamala Harris and her husband Douglas Emhoff attend a memorial for the passengers and crew of United Flight 93, Saturday Sept. 11, 2021, in Shanksville, Pa., on the 20th anniversary of the Sept. 11, 2001, attacks. Secretary of Interior Deb Haaland and Gordon Felt, brother of Edward Porter Felt and President of Familes for Flight 93, are right. (AP Photo/Jacquelyn Martin)

April Horton, left, Blake Edward Schaffer, 10, and Andrea Stauter, right, sisters and nephew of Petty Officer First Class Edward Earhart, who was killed in the Pentagon on 9/11, pose for a family photo following an observance ceremony at the Pentagon in Washington, Saturday, Sept. 11, 2021, on the morning of the 20th anniversary of the terrorist attacks. Nephew Blake Edward Schaffer was named honoring Earhart. (AP Photo/Alex Brandon)

A screen displays a video of former President George W. Bush during an event to commemorate the 20th anniversary of the Sept. 11, 2001, terrorist attacks, Saturday, Sept. 11, 2021, in Springfield, Va. (AP Photo/Luis M. Alvarez)

Bagpipers stand at attention 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)

A member of FDNY rings a bell during the singing of the National Anthem at the annual 9/11 Commemoration Ceremony at the National 9/11 Memorial and Museum on September 11, 2021 in New York City. During the ceremony, six moments of silence were held, marking when each of the World Trade Center towers was struck and fell and the times corresponding to the attack on the Pentagon and the crash of Flight 93. The nation is marking the 20th anniversary of the terror attacks of September 11, 2001, when the terrorist group al-Qaeda flew hijacked airplanes into the World Trade Center, Shanksville, PA and the Pentagon, killing nearly 3,000 people. (Photo by Michael M. Santiago/Getty Images)

US Secretary of Defence Lloyd Austin speaks during a remembrance ceremony to mark the 20th anniversary of the 9/11 attacks, at the Pentagon in Washington, DC on September 11, 2021. – America marks the 20th anniversary of 9/11 Saturday with solemn ceremonies given added poignancy by the recent chaotic withdrawal of troops from Afghanistan and return to power of the Taliban. (Photo by SAUL LOEB / AFP) (Photo by SAUL LOEB/AFP via Getty Images)

Bruce Springsteen performs during the annual 9/11 Commemoration Ceremony at the National 9/11 Memorial and Museum on September 11, 2021 in New York City. During the ceremony six moments of silence were held, marking when each of the World Trade Center towers was struck and fell and the times corresponding to the attack on the Pentagon and the crash of Flight 93. The nation is marking the 20th anniversary of the terror attacks of September 11, 2001, when the terrorist group al-Qaeda flew hijacked airplanes into the World Trade Center, Shanksville, PA and the Pentagon, killing nearly 3,000 people. (Photo by Chip Somodevilla/Getty Images)

(L-R) Former President Bill Clinton, former First Lady Hillary Clinton, former President Barack Obama, former First Lady Michelle Obama, President Joe Bien, First Lady Jill Biden, former New York City Mayor Michael Bloomberg, Bloomberg’s partner Diana Taylor, Speaker of the House Nancy Pelosi (D-CA) and Senate Minority Leader Charles Schumer (D-NY) stand for the national anthem during the annual 9/11 Commemoration Ceremony at the National 9/11 Memorial and Museum on September 11, 2021 in New York City. During the ceremony six moments of silence were held, marking when each of the World Trade Center towers was struck and fell and the times corresponding to the attack on the Pentagon and the crash of Flight 93. The nation is marking the 20th anniversary of the terror attacks of September 11, 2001, when the terrorist group al-Qaeda flew hijacked airplanes into the World Trade Center, Shanksville, PA and the Pentagon, killing nearly 3,000 people. (Photo by Chip Somodevilla/Getty Images)

Former New York City Mayor Rudy Giuliani (C) attends the annual 9/11 Commemoration Ceremony at the National 9/11 Memorial and Museum on September 11, 2021 in New York City. During the ceremony six moments of silence were held, marking when each of the World Trade Center towers was struck and fell and the times corresponding to the attack on the Pentagon and the crash of Flight 93. The nation is marking the 20th anniversary of the terror attacks of September 11, 2001, when the terrorist group al-Qaeda flew hijacked airplanes into the World Trade Center, Shanksville, PA and the Pentagon, killing nearly 3,000 people. (Photo by Chip Somodevilla/Getty Images)

Delegates from the United States Embassy including Acting Ambassador, Philip T Reeker (L), Charge d’Affaires, attend the changing of the Guard at Windsor Castle to mark the 20th anniversary of the 9/11 terror attacks in the US, on September 11, 2021. – In a royal tribute to the dead, who included 67 Britons, the US anthem was played on Saturday by fur-hatted Welsh Guards at the Changing of the Guard ceremony at Windsor Castle. (Photo by Steve Parsons / POOL / AFP) (Photo by STEVE PARSONS/POOL/AFP via Getty Images)

A beam of light is visible over the Lincoln Memorial, the day before the 20th anniversary of the Sept. 11 terrorist attacks, as part of the Towers of Light Tribute, Friday Sept. 10, 2021, in Washington. (AP Photo/Jose Luis Magana)

An American flag is unfurled at the Pentagon in Washington, Saturday, Sept. 11, 2021, at sunrise on the morning of the 20th anniversary of the terrorist attacks. The American flag is draped over the site of impact at the Pentagon. In the foreground, the National 9/11 Pentagon Memorial, opened in 2008 adjacent to the site, commemorates the lives lost at the Pentagon and onboard American Airlines Flight 77. (AP Photo/Alex Brandon)

An American flag hangs from the side of the Pentagon to commemorate the 20th anniversary of the 9/11 attacks, on September 11, 2021, in Washington,DC. – America marks the 20th anniversary of 9/11 Saturday with solemn ceremonies given added poignancy by the recent chaotic withdrawal of troops from Afghanistan and return to power of the Taliban. (Photo by SAUL LOEB / AFP) (Photo by SAUL LOEB/AFP via Getty Images)

An American flag is unfurled at the Pentagon in Washington, Saturday, Sept. 11, 2021, at sunrise on the morning of the 20th anniversary of the terrorist attacks. The American flag is draped over the site of impact at the Pentagon. In the foreground, the National 9/11 Pentagon Memorial, opened in 2008 adjacent to the site, commemorates the lives lost at the Pentagon and onboard American Airlines Flight 77. (AP Photo/Alex Brandon)

A rose is seen at the National 9/11 Pentagon Memorial that commemorates the lives lost at the Pentagon and onboard American Airlines Flight 77 at the Pentagon in Washington, Saturday, Sept. 11, 2021, at sunrise on the morning of the 20th anniversary of the terrorist attacks. (AP Photo/Alex Brandon)