"Avengers: Age of Ultron"
Yet even after the final figures for the domestic debut roll in, Earth's Mightiest Heroes have another challenge: conquering the Chinese box office.
If recent history is any indicator, Iron Man, Captain America and the gang will fare well in the world's second-largest movie market when it debuts there on May 12. Though superheroes are new to the country, China has become the most lucrative foreign market for comic book films.
Still, China's tightly regulated movie industry—and the still-developing tastes of its audiences—can make it difficult to predict exactly which U.S. movies will not just draw big audiences, but break out and go stratospheric.
"The grosses [for superhero films] have been climbing very nicely," said Rob Cain, a China film industry specialist and president of Pacific Bridge Pictures. "As Marvel's universe builds, we're going to see bigger numbers for these pictures."
Last year, caped crusaders smashed through yet another threshold in the Middle Kingdom. For the first time, each of the four live-action superhero movies released in 2014—and Disney's animated "Big Hero 6"—made more than 10 percent of worldwide box office earnings in China. The first Avengers romp earned just 5.6 percent of its global gross there.