In the weeks leading up to the 78th anniversaries of the U.S. atomic bombings of Hiroshima and Nagasaki, Americans rushed to theaters for "Oppenheimer," a new biopic about the life of the pivotal figure behind the development of nuclear weapons.

The film has made more than $600 million at the global box office since its July 21 release, becoming one of the highest grossing World War II-related movies ever, according to U.S. media reports.

A movie billboard for "Oppenheimer" is pictured in New York on July 21, 2023. (Kyodo)

The achievement in part has been propelled by a wave of viral, imaginative mashups flooding social media platforms, juxtaposing imagery inspired by the biopic with that of "Barbie," a satirical comedy released at the same time which has broken the $1 billion mark at the global box office.

Many of the memes go with the hashtag "Barbenheimer," a portmanteau of the two blockbusters.

According to Know Your Meme, the first post that went viral under the hashtag was on Jan. 1 this year, garnering more than 210,000 views in all. As both films closed in on their debut, fans began to make their own "Barbenheimer" memorabilia.

The National Association of Theatre Owners, representing 35,000 screens in the United States, said that more than 200,000 people bought tickets to watch "Oppenheimer" and "Barbie" on the same day during opening weekend.

Paul Dergarabedian, a senior media analyst at Comscore Inc., a Virginia-based company that tracks social media and box office trends, said that the fan-made memes acted as advertisements for both films.

Some people who might not have seen either film may have ended up seeing both, Dergarabedian said. "That is very unusual, very cool," he added.

People in the United States interacted with the "Barbenheimer" memes 44.1 million times on TikTok, 15.4 million on Instagram and 1.2 million on Twitter, now called X, according to Comscore data from April 1 to July 26.

Kelsi Parsons, a 27-year-old worker in human resources, said at a theater in Manhattan that while she might have seen both anyway, "seeing them as a meme added to the hype and excitement around it."

The memes, however, have not gone down so well in Japan, with one featuring the Barbie star with her hair being replaced with a mushroom cloud raising eyebrows.

The U.S. promoter of "Barbie" was criticized after it engaged positively with some of the Barbenheimer posts linking its main character to atomic bomb-related imagery. The film's Japanese distributor expressed regret and Warner Bros. later apologized over the controversy.

While Barbie was released in Japan last Friday, there is currently no information on whether Oppenheimer will be shown in the country.

"People that participated in Barbenheimer memes did not think they were making light of the bombings of Hiroshima and Nagasaki by doing that," said Don Caldwell, chief general manager at Know Your Meme.

"They are tying the mushroom cloud more to just a symbol for the film, rather than a symbol for the bombing," he said.

Unlike Japan, where anti-nuclear weapons sentiment is strong, the United States has a postwar history of producing a variety of merchandise with mushroom clouds and atomic bomb images.

James Stemm, a curator at the National Museum of Nuclear Science and History in New Mexico, said nuclear images first appeared in advertising and other products at the end of 1945, "almost immediately" after the atomic bombs were developed and used.

The word "atomic" that was plastered on objects including toys was synonymous with the words "new," or "scientific advancement," he said.

"It was a reaction by the people trying to understand this new technology, this new science they had just been introduced to very dramatically and horrifically."

According to Stemm, part of the reason the atomic imagery showed up on children's toys was because the U.S. government in the early 1950s encouraged people to study nuclear science.

In the mid-1960s, however, nuclear imagery stopped being wholly positive and started to show the consequences of nuclear weapons use as the anti-nuclear movement gained steam, Stemm said.

An engineer in his 20s who only wanted to be identified as Owen said earlier this month that, like many other Oppenheimer fans, he was not aware of the anniversaries of Hiroshima and Nagasaki, which fall on Aug. 6 and 9.

"It is probably something I will research," he said.

Related coverage:

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Warner Bros. apologizes over A-bomb-related social media flap