A couple of years ago I ran across a video made by the Kodak Company back in the late 1920s. It was a test of their color film for moving pictures. The short movie consisted of children and a smiling young woman, with no sound. As I watched the film, it was hard to wrap my head around the simple fact that everyone involved in the project of creating those images, this remarkable new technology at the time, were all long dead.

Then the History Channel broadcast films of World War I that were shot in color: startling indeed, since I hadn’t realized that techniques were even possible so long ago, between 1916 and 1918.

It is one thing to see old black and white films. We’re used to those images of the twenties and before, with the timing off , so that the movements of people are hurried and jerky. Silent, black and white movies telegraph to us that they are ancient, the long ago past. That the people in such films no longer live is not as shocking.

But to witness films of young people, beneath blue skies, with green trees, with the world just as alive and vibrant as today—that forces us to consider that our present is equally as fleeting for us as it was for them, and that the our present will likewise all too soon become the long ago yesterday dimly witnessed second hand by those that follow us. “Today,” to paraphrase the lyrics to the Late, Late Show with Craig Ferguson, is “tomorrow’s yesterday.”

“Memento mori” is a Latin phrase that translates the cheerful thought “Remember, you will die.” It is a phrase used for a certain genre of art that dates back to antiquity, whose purpose was to remind people of their mortality. Although antique color movies were not created as “memento mori,” they have served that purpose for me.

When Roman generals returned victorious, they were given a parade called a “Triumph.” Battle hardened soldiers would march at the head of that parade, while behind them trudged their prisoners of war, destined to slavery. Behind them trundled the cartloads of the riches taken from the conquered nation, along with exotic beasts. Last of all, like the Santa in the Macy’s Christmas parade, the general stood waving in his horse drawn chariot. According to Tertullian, a slave stood with him, whispering in his ear, “Respice post te! Hominem te esse memento! Memento mori!”: “Look behind you! Remember that you are but a man! Remember that you will die!”

Since those days, both in literature and representational art, there has been a steady stream of work designed to do for ordinary people what the Romans did to their victorious generals. It is not uncommon to discover it in cemeteries—at least the old style cemeteries, with full headstones and such, especially those in church yards.

But the modern western world, in recent years, has done to mortality what the Victorians did to sex: it has covered it up and become ashamed. We don’t want to talk about it or think about it. While our arts and media are more than happy to discuss and flaunt sex, while books on the subject regularly lead the best seller list, when it comes to our inevitable mortality—well, “how about them Dodgers.”

We are now more than ten years into a war against extremist elements in the Moslem world. Our brave soldiers fight daily in Iraq, Afghanistan, and elsewhere. Our special forces teams battle hidden conflicts across the globe. Most of us have friends or relatives who have gone to fight. Some have not returned. Many of us know people who perished on 9/11.

The longer we live, the more frequently we are reminded of the transience of our residence here. Teenagers lose one or two classmates from car accidents or illnesses. Newly marrieds may lose offspring to stillbirth and SIDS. Before we know it, we stop attending baby showers and find ourselves regularly at funerals for parents and friends. With each loss, we are forced to consider what we’d really rather not think about, even as we live in a society that refuses to prepare for it, like the grasshopper in the Aesop’s fable that failed to plan for winter.

Even as we find the wrinkles increasing, the hair turning gray, we ignore the implication. We resist putting together our wills, or putting our affairs in order. We don’t think to pass along recipes, or even the passwords to our bank, email, and social networking accounts. Why should we? Are we going somewhere?

We plan for earthquakes, rain, and winter. We would do well to plan for the unavoidable end of our world.

As the Borg from Star Trek would intone: resistance is futile. You will be assimilated. Memento mori.