Americans Mark 19th Anniversary of 9/11 Attacks

Flowers are placed in the inscribed names of the deceased at the National September 11 Memorial and Museum, Friday, Sept. 11, 2020, in New York. (AP Photo/John Minchillo)

A giant American flag is unfurled as the national anthem is plated at the National September 11 Memorial and Museum, Friday, Sept. 11, 2020, in New York. (AP Photo/John Minchillo)

President Donald Trump speaks at a 19th anniversary observance of the Sept. 11 terror attacks, at the Flight 93 National Memorial in Shanksville, Pa., Friday, Sept. 11, 2020. (AP Photo/Gene J. Puskar)

Democratic presidential candidate former Vice President Joe Biden greets Vice President Mike Pence at the 19th-anniversary ceremony in observance of the Sept. 11 terrorist attacks at the National September 11 Memorial & Museum in New York, on Friday, Sept. 11, 2020. (Amr Alfiky/The New York Times via AP, Pool)

Mourners pause at the north reflecting pool as flowers are placed in the names of the dead 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)

A National Park Service ranger rehearses the wreath laying ceremony that President Donald Trump will participate in during a memorial service at the Wall of Names at the Flight 93 National Memorial in Shanksville, Pa., Friday, Sept. 11, 2020.(AP Photo/Gene J. Puskar)

Visitors to the Flight 93 National Memorial in Shanksville, Pa., unfold a flag commemorating Flight 93 for a memorial service on Thursday, Sept. 10, 2020, as the nation prepares to mark the 19th anniversary of the Sept. 11, 2001, attacks. (AP Photo/Gene J. Puskar)

US Army Sgt. Edwin Morales, center right, salutes after places flowers for fallen FDNY firefighter Ruben D. Correa at the National September 11 Memorial and Museum, Friday, Sept. 11, 2020, in New York. The names of nearly 3,000 victims of the Sept. 11, 2001 terror attacks will be read by family members at a ceremony organized by the Tunnel to Towers Foundation. (AP Photo/John Minchillo)

FILE - In this Sept. 11, 2001, file photo, smoke rises from the burning twin towers of the World Trade Center after hijacked planes crashed into the towers, in New York City. The coronavirus pandemic has reshaped how the U.S. is observing the anniversary of 9/11. The terror attacks' 19th anniversary will be marked Friday, Sept. 11, 2020, by dueling ceremonies at the Sept. 11 memorial plaza and a corner nearby in New York. (AP Photo/Richard Drew, File)

Diane Massaroli holds flowers flags and photo of her husband Michael Massaroli who died during the Sept. 11, 2001 attacks at the World Trade Center, before a ceremony organized by the Tunnel to Towers Foundation, in New York. The names of nearly 3,000 victims of the Sept. 11, 2001 terror attacks are being read by family members. (AP Photo/Mark Lennihan) (AP Photo/Mark Lennihan)

Lorna O'Hara holds a poster of her cousin, Brian Bilcher, a New York City firefighter who died on Sept. 11, 2001, during the attacks at the World Trade Center, before a ceremony organized by the Tunnel to Towers Foundation, Friday, Sept. 11 2020, in New York. The names of nearly 3,000 victims of the Sept. 11, 2001 terror attacks are being read by family members. (AP Photo/Mark Lennihan)

Mackenzie, right, and Madison Miller from Avonmore, Pa., visit the Wall of Names at the Flight 93 National Memorial in Shanksville, Pa., Thursday, Sept. 10, 2020, as the nation prepares to mark the 19th anniversary of the Sept. 11, 2001, attacks. The Wall of Names honors the 40 people killed in the crash of Flight 93. (AP Photo/Gene J. Puskar)

A beam of light is seen near to the Lincoln Memorial, as part of the Towers of Light Tribute marking the 19th anniversary of the 9/11 attack on the Pentagon, Sept. 9, 2020, in Washington. (AP Photo)