It is, in the words of its director, the story of the most important person who ever lived.

And on Sunday, "Oppenheimer" completed its indomitable march towards Hollywood's most important prize, winning the Academy Award for best picture.

Christopher Nolan's masterpiece -- the story of the brilliant physicist who oversaw the invention of the atomic bomb, changing the world forever -- is a grand, old-fashioned blockbuster for grown-ups.

Shot on a $100 million budget, "Oppenheimer" spared no expense, and bucked the recent trend of smaller, indie movies winning the most prestigious Oscar.

A cast was assembled from Tinseltown's top A-list, a replica of 1940s Los Alamos was secretly constructed on a mountain in New Mexico, and the test of the first-ever nuclear bomb was recreated with vast quantities of real explosives.

The effect was spellbinding, for audiences and critics alike.

Released last July, "Oppenheimer" immediately drew rave reviews and shattered box office expectations.

It went on to collect nearly $1 billion around the world, and won a total of seven Academy Awards at Sunday's gala.

Robert Downey Jr wins best supporting actor Oscar for 'Oppenheimer'

'DREAM AND NIGHTMARE'

Nolan, the director behind ambitious blockbusters from "Inception" to "The Dark Knight," had recently finished making "Tenet" when he stumbled upon "American Prometheus," the 2005 Pulitzer Prize-winning biography of J. Robert Oppenheimer.

He was instantly inspired to bring a life of ambitious genius and hubristic tragedy, of "dream and nightmare," to the biggest possible screen.

Oppenheimer, having attained global fame as the "father of the bomb," soon came to bitterly regret the consequences of his invention, campaigning for nuclear disarmament and eventually having his reputation shattered due to his former Communist sympathies.

"His story offers no easy answers. But it offers some of the most fascinating and interesting paradoxes that I've ever encountered," said Nolan.

While Nolan is most often associated with genres such as sci-fi, he decided to structure "Oppenheimer" along three other film tropes -- hero's journey, heist movie and courtroom drama.

The scientist embarks on a quest to race the Nazis to the bomb, assembles a crack team of experts to get the job done, and is forced to plead his case in court, with the action constantly rotating between the three.

Cillian Murphy, a frequent and trusted collaborator from five previous Nolan films, was cast in the titular role, with Robert Downey Jr as his bitter, furtive rival, Lewis Strauss.

The two men won best actor and best supporting actor on Sunday, respectively.

A stellar ensemble cast included Matt Damon, Emily Blunt, Florence Pugh, Kenneth Branagh, Gary Oldman and Rami Malek.

"This was like 'Battle of the Bulge' or 'Ben-Hur,' one of those movies where you just look around and every single person in the movie is somebody that you admire," said actor Matthew Modine, in a book accompanying the film.

BARBENHEIMER 

There is no doubt the film benefited commercially from the viral "Barbenheimer" phenomenon, which saw thousands flock to movie theaters for a double bill including the wildly different "Barbie."

By coincidence, the two movies from rival studios had been penciled in for the same release date, with each refusing to budge.

"I'm glad neither of us did. It worked out pretty well," producer Charles Roven later told AFP.

Even so, few could have predicted the astonishing mainstream popularity of a lengthy movie shot partly in black-and-white, about such a weighty topic, and structured largely around complex science and highly technical government hearings.

"If you're sitting around wondering what the box office is going to be on a three-hour movie about a guy named Oppenheimer who invented the atom bomb, you're not sitting there and saying, 'It's going to do almost a billion dollars,'" recalled Roven.

"So the fact that it did -- and the critical acclaim -- is just so rewarding."

The movie was Nolan's first in two decades not to be released by Warner Bros.

The director had fallen out with his usual studio over its decision to put films on streaming first during the Covid-19 pandemic, jumping ship to its rival Universal.

"Oppenheimer" was also disrupted by last year's Hollywood strikes. Its cast walked out of the London premiere in solidarity with fellow actors as the walkout was called last summer.

Since then, it has been plain sailing, as the movie has scooped up the biggest prizes at every awards season ceremony, from the Golden Globes to the Screen Actors Guild Awards.

The best picture Oscar is its final -- and most important -- reward.

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© Agence France-Presse