“What happened?”

Ken Burns opens his 10-night, 18-hour opus The Vietnam War with the sound of a helicopter’s rotor blades beating hypnotically against a visual slipstream of grainy film footage from the era, images from “the American War,” as it came to be known in Vietnam itself, “in-country” with the Marines and street protests “back in the world.”

“Coming home from Vietnam was close to traumatic as the war itself,” Vietnam veteran and ex-Marine Karl Marlantes (right) says in the film’s first spoken words, nearly a  full minute into the first installment, Episode One: Déjà Vu (1858-1961).

“For years, nobody talked about Vietnam,” he says, reminiscing slowly but clearly. “The whole country was like that. It was so divisive . . .  It’s only been very recently, I think, with the baby boomers, that people are finally starting to say: ‘What happened? What happened?’”

So far, The Vietnam War looks and sounds like any other Ken Burns visual history viewers have become familiar with, from The Civil War to The Roosevelts. It’s all there: the signature witness testimony, the archival film footage from the era, the historical experts and pointed, simply enunciated narration by longtime Burns collaborator Peter Coyote.

Just five minutes later, the picture changes. This one is going to be different. This one is contemporary. This one is going to cut close to the bone. As close as any Burns film has. Here. Now.

Many viewers who tune into The Vietnam War — even if it’s only for a moment — will be old enough to remember those times as they were a-changin'. Many of those viewers will have had an intensely personal experience, whether they fought in the war itself, lost a beloved family member or lived through the turbulent social upheaval back home — “back in the world,” as US soldiers serving “in-country” came to know home.

The Vietnam War is unlike any film Burns and his creative partner Lynn Novick have ever made. It’s the contemporary milieu, of course, and the political climate of our times. It’s partly the nervous, urgent, constantly shifting background music by Nine Inch Nails members Trent Reznor and Atticus Ross, and the rich, booming stereo of bomb blasts detonating in the background. Mostly, though, it’s the sense that this film is personal to Burns himself — perhaps the most personal film he has made. He graduated from high school in Ann Arbor, Michigan in 1971. This could have been him.

There’s another difference. Seven minutes into the film, North Vietnamese Army veteran Bao Ninh, his hair as white as any American G.I. to have lived through those times, proffers his own testimony in his native Vietnamese, subtitled. “It has been forty years,” he says, haltingly. “Even the Vietnamese veterans, we avoid talking about the war. People sing about victory, about liberation. They’re wrong. Who won and who lost is not a question. In war, no one wins or loses. There is only destruction. Only those who have never fought like to argue about who won and lost.”

Throughout the next hour-and-a-half of Episode One, and over the course of the 16-and-a-half hours that follow, The Vietnam War will toggle back and forth between the American perspective and the Vietnamese perspective, both South and North. That alone makes this film unique. The Vietnamese story has never really been told.

In some ways, Sunday’s opening chapter is not representative of the chapters that follow. The opener covers the years 1858 to 1961 — more than half a century — and begins with the administration of Woodrow Wilson and the early days of colonial occupation in French Indochina, or Indochine française as les Français knew it.In some ways, Sunday’s opening chapter is not representative of the chapters that follow. The opener covers the years 1858 to 1961 — more than half a century — and begins with the presidential administration of Woodrow Wilson and the early days of France’s colonial occupation of French Indochina, or Indochine française as les Français knew it.

Burns has never been intimidated by the sweep of history, and the opening hour-and-a-half takes in the Japanese invasions of mainland Asia in the Second World War, war in the Pacific and the dropping of the atom bomb, political and social upheaval in China, the consolidation of Communist power in the post-war Soviet Union, the Korean War, the new nuclear age and the slow but steady dissolution of colonialism the world over, and in French Indochina specifically.

Burns and Novick take on the big question — how did the US become mired in Vietnam and, more importantly, why — and it’s both hypnotic and harrowing to watch.

The French made a mess of it, but what makes these early hours of The Vietnam War so compelling is the knowledge in hindsight that, once America got involved, the most powerful nation on Earth would fare little better, despite the best of intentions and the greatest of efforts.

As a living, breathing document of recent history, The Vietnam War is an astounding achievement. The first installment is fascinating, gripping and hypnotic by turns.

“Vietnam is burning,” Lt. Col. Peter Dewey of the US Office of Strategic Services, is quoted as saying in a cable from Saigon. “The French and British are finished here.” The United States, Dewey concluded, “ought to clear out of Southeast Asia.” This was on Sept. 24, 1945.

The real heart of The Vietnam War, though, the part liable to keep the viewer awake at nights — the personal stories, the human cost, the implications for our times  — is yet to come. Episode One: Déjà Vu is a valuable lesson in history, well-made and endlessly fascinating, but it’s mere prologue for what’s to come.

If ever there was a program that demands that the viewer to come back for more, this is it. There are moments in the nights and weeks to come that are unforgettable.

TV Worth Watching will preview Episode Two: Riding the Tiger (1961-1963) on Monday, Sept. 18. The Vietnam War airs Sundays through Thursdays on PBS at 8 p.m. ET through Sept. 28 (check local listings).