Sunday marked the 84th anniversary of what is arguably the 20th-century’s single-most significant event, at least as far as the United States is concerned.

For it was 84 years ago that morning that more than 350 carrier-based warplanes of the Empire of Japan paid an unannounced visit to the U.S. Pacific Fleet stationed at Pearl Harbor, Hawaii. Several hours later, four battleships had been sunk, four others damaged and an array of other ships damaged or destroyed. More than 2,300 service personnel were killed and another 1,300 wounded.

The event plunged America headlong into World War II and altered forever the course of world history and human events. Yes, Pearl Harbor was a big deal but not because of stark statistics, as awful as they were. It’s because of the people who found themselves front and center that morning — the people who survived and, perhaps, most importantly, those who didn’t — and what their collective sacrifice says about us as a nation.

The U.S. had been badly bruised that morning; to a nation not yet accustomed to the human cost of war, the casualty figures were particularly horrifying. It’s not hard to envision a lessor nation folding and suing for peace.

But that didn’t happen. In the months and years that followed, U.S. forces and its allies swept across Europe and the Pacific. Other great battles were fought and won and in 1945 the allies claimed victory.

But it all started with the unexpected Japanese attack on Pearl Harbor, an act that outraged and insulted the American sense of fair play.

We should never forget the sacrifices that took place that day. Because if we ever do, we will have lost something fundamental from what it means to be an American.