Walt Disney Co.'s superhero epic "Avengers: Endgame" became the first movie to gross more than $1 billion in its debut at the world-wide box office.

The Marvel Studios blockbuster, powered by record-setting hauls in the U.S. and China, collected an estimated $1.2 billion in its first five days of release. An estimated $350 million of that total came from the U.S. and Canada, an amount that blew past the previous opening-weekend record set last year by "Avengers: Infinity War" by about $92 million.

Hollywood had expected "Endgame" to set a record, but the movie's performance stretched the limit of what many studio executives thought was even possible in an opening weekend. Demand forced exhibitors to dedicate about half the nation's screens to the superhero movie, with dozens of locations screening it round-the-clock and even 2 a.m. showtimes selling out.

Over the past 11 years, Marvel's superheroes have reigned at the box office, a result of a strategy set by the studio in 2008 with the release of "Iron Man." Interconnected story lines and characters—from Thor to Doctor Strange to Captain Marvel—have helped place Disney on an unprecedented winning streak at the box office. In just over a decade, Marvel's success has prompted rival studios to hunt for their own franchises, provided a much-needed boon to a struggling exhibition industry and turned comic-book superheroes into one of America's most popular exports.

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An early premiere of 'The Avengers: Endgame' in La Paz, Bolivia. PHOTO: DAVID MERCADO/REUTERS[/caption]

"Endgame" could become the highest-grossing movie of all time, beating the record set by "Avatar," which made $2.79 billion globally in 2009. After just five days of release, it is already No. 18 on the world-wide box-office chart.

To become the top-grossing movie in the U.S. and Canada, it will need to beat the $936 million collected by Disney's "Star Wars: The Force Awakens" in 2015. (When figures are adjusted for inflation, "Gone With the Wind" holds the top spot, according to Box Office Mojo, with $1.8 billion.)

In China, once an afterthought to studios but now the world's second-largest box-office market, the movie is virtually guaranteed to become the highest-grossing import of all time, with $331 million grossed so far—only about $60 million behind the current record holder, 2017's "The Fate of the Furious."

The overseas performance of "Endgame"—$859 million in five days—speaks to the staggering rise in international box-office receipts over the past decade. The first "Iron Man" collected about 46% of its total box office from overseas markets. When "Infinity War" was released last year, the international market accounted for 67% of the total gross.

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Demand forced exhibitors to dedicate about half the nation's screens to the superhero movie, with dozens of locations screening it round-the-clock. PHOTO: WALT DISNEY/MARVEL/ASSOCIATED PRESS[/caption]

"Endgame" caps a series of 21 previous Marvel superhero movies that began with Robert Downey Jr. starring as Tony Stark in 2008's "Iron Man" and has included smash hits such as "Guardians of the Galaxy," "Black Panther" and March's "Captain Marvel." A sequel to last year's "Infinity War," "Endgame" has been marketed by Disney as the culmination of the 11-year saga, though more Marvel movies are already scheduled on the release calendar.

"Infinity War" set a record for a global debut last April with $640 million, a figure that excluded Chinese box-office receipts. That movie ended on a cliffhanger that saw half the superheroes vanish into dust.

"The pent-up factor, off the ending of 'Infinity War' and on the heels of 'Captain Marvel,' drove people to show up," said Cathleen Taff, Disney's head of distribution.

Fans around the world filled auditoriums, worried about having some of the movie's biggest surprises spoiled on social media.

Josh Martin, a 28-year-old animator from Houston, wanted to see "Endgame" as quickly as possible—which meant attending a 2 a.m. screening with his brothers early Friday morning.

At work on Friday, he worried about spoiling the movie for colleagues, until he found a co-worker who had already seen it three times—at an early Thursday evening showing, a late night Thursday showing and then finally at an early morning Friday showing.

Like many fans, Mr. Martin has followed the stories of the Marvel superheroes for more than a decade.

"It's like part of the family when you see Tony Stark up there," he said.

Raamiz Khan, a 14-year-old Pakistani student who has lived most of his life in Dubai, joined about a dozen school friends for a Thursday screening of the movie at a theater in Dubai's snazzy Marina Mall.

"The theater was packed…people were jumping and screaming throughout," he said. "Many just forgot where they were sitting and ended up on the stairs."

In India, "Endgame" opened on more than 2,500 screens and was shown in English and three other Indian languages.

The family of Armaan Nalli, 15 years old, usually goes to local-language movies together, but he has been a Marvel fan for most of his life.

The moviegoers were so excited to get in that he got pushed past the 3-D glasses stand and had to go back to the entrance after finding a seat.

"People stood up and applauded at the credits," he said.

Disney's superhero success has forced rivals to mimic the approach, most notably at the DC Comics franchise from AT&T Inc.'s WarnerMedia, the studio behind films like "Wonder Woman" and "Justice League."

It has also consolidated market share among the biggest releases Hollywood has to offer. Disney is now behind nine of the 10 biggest domestic opening weekends in history—Universal Pictures' "Jurassic World" is the lone exception among Disney hits like the last two "Star Wars" movies and "Incredibles 2."

For theater owners grappling with at-home competition from Netflix Inc., the boost from a new Disney hit goes beyond just ticket sales. The nation's largest exhibitor, AMC Entertainment Holdings Inc., said Sunday it had set company records in food-and-beverage sales on Friday and Saturday.

About 45% of global ticket sales over the weekend were for premium-priced 3-D screenings, according to RealD Inc., and IMAX Corp. said its previous opening-weekend record was nearly doubled by "Endgame" returns of about $91.5 million in its big-screen auditoriums.

"It speaks to what works right now, which is people want big events and people can galvanize on a global basis," said IMAX Entertainment President Megan Colligan.

Opening-weekend audiences approved of "Endgame," giving it a rare "A+" grade, according to the CinemaScore market research firm, a response that could signal repeat customers in the weeks to come.