Everyone old enough to watch television on Sept. 11, 2001 knows where they were when the planes hit the north and south towers and the Pentagon. The terrorist attacks using four commercial aircraft as weapons changed history in a way that seems unforgettable to those who lived through it. For some it has already faded; that is proving to be a danger.

The people bringing this lapse of memory to attention are members of the group Friends of Flight 93, who support the Flight 93 National Memorial in Stoystown, Penn. When they volunteer on the site where United Flight 93 crashed into a field, they find visitors are often surprised to hear about what happened there. The guides tell them the story of passengers and crew who knew, from mobile phone calls with friends and family on the ground, that three other planes had hit major targets. Rather than let their flight slam into the U.S. Capitol or the White House, they fought for control of the plane. All aboard died when it crashed.

The Friends have opened nominations for the Flight 93 Heroes Award, "searching for extraordinary people across the country who embody the spirit and resilient courage of the 40 passengers and crew members of Flight 93, who displayed incredible heroism and bravery on 9/11 in the skies over Shanksville, Pa." The deadline is July 4.

An annual award should help keep alive the memory of ordinary Americans responding with a sacrifice that saved other lives and preserved the center of U.S. government. But the lack of awareness that prompted the award is confounding, given that the images of 9/11 are seared into the minds of those who witnessed it.

We should ask these questions: How could anyone who remembers the 9/11 near-miss on the Capitol wave away the implications of the Jan. 6, 2021 assault on that very building? Same target, same destructive purpose — only this time the attackers were Americans. From the looks of those who stormed in that day, most are old enough to clearly recall 2001.

Both assaults mean that a destructive force wanted to obliterate the seat of government and would, even though unsuccessful, rewrite history. The most influential nation in the world changed in that September and in this January. The Associated Press reported in announcing the award that many states have no particular requirement to teach about the most infamous day between Pearl Harbor and this year. If they don't teach 9/11, don't expect them to contend with the political pressures around Jan. 6.

Connecticut, it is good to know, renewed its commitments to teaching U.S. History and social studies in recent years. The state has added requirements and resources for African-American, Black, Puerto Rican and Latin studies to fill in longstanding silences on those cultures.

Future generations will know what happened on history-changing occasions only if they are taught about them. They have a right to know, and as future responsible and patriotic citizens they will need to decide what obligations for freedom those events put into motion.

This is a key moment to recall that when history is preserved and studied, it gives up an ever-expanding Big Picture. On a smaller scale, a recent volunteers' project to transcribe a log from a whaling ship led Laurie Deredita, the librarian of the New London Maritime Society to the identity of the man who kept the journal: Frederic Olney, the third mate on the Merrimac in 1844, was a person of color and lived in Canterbury. The log project was supposed to add to knowledge about whaling, but it went much further and gave insight into an extraordinary life that sounds like material for the state's newest curriculum requirements.  

Mr. Olney's log is a small but critical piece of a Connecticut industry and who worked in it, but the principle of knowing the history is the same: What happened, and what does it mean for the future? Everyone needs to know.

Lisa McGinley is a member of The Day Editorial Board.