The Titanic, World Wars, Jonestown Massacre, Vietnam War, Korean War, the Holocaust, the genocide of Africa, the assassination of a president or other head of state., the California Freeway collapse, even the Oklahoma bombing. All of these things were terrible events and should be remembered.
Animals return, plants reestablish themselves and new people settle again in the area.
An older person might remember the event for a time, books and articles are there for the youngsters, but except for technical personnel, such as architects, geologists, or the like, the memory fades. And so it is with astronomy. A star will flare silently in the night, a few meteorites streak across the sky, a fog covers the moon. Most people are asleep. Exhausted from their daily labors, they sleep with no inkling of stellar events.