A day that history will mark… but the sands of time tend to eat away at the immediacy of our memories as we become more preoccupied with the challenges of the present. We never forget, but we tend to remember less often as well.

A whole generation has been born and raised since that fateful moment 18 years ago. They will be old enough to vote in the next presidential election as they stare down new fears and anxieties. That is how time works. We need to teach our history, but not be imprisoned by it.

I have so many dates seared in my mind… December 7 (1941)… June 6 (1944)… November 22 (1963)… April 4 (1968)… August 9 (1974) – just to name a few. They were and are the real backdrop for my time, and those who were on life’s journey with me. I want to tell my grandchildren about what they meant. But like me reading about July 4 (1776) or April 15 (1865), they will note them and maybe remember them, but not feel them as I do.

We are on this earth but a short time. Our lives are marked with memories happy and sad, personal, communal, national, and global. Time strides on. The Earth spins. We pause, to think about the past… and the future.

(A version of this first appeared on Dan’s Facebook page on September 11, 2017)

Watch above to see Dan Rather, Bryant Gumbel and Harold Dow report on the events the morning of September 11, 2001, as they unfolded.