“Avengers: Endgame” is preparing for a staggering debut between $250 million and $268 million in North America alone. Unprecedented anticipation surrounding the Marvel juggernaut has some particularly optimistic box office watchers tossing around even higher numbers, estimating the superhero tentpole could clear nearly $300 million in ticket sales in its first three days.

If any film could reach that benchmark, “Avengers: Endgame” certainly seems like the best contender. But is it even possible for any single film to top that number in one weekend? The naturally limited amount of available seats and showtimes in a given day makes that a difficult pinnacle to reach for any movie. The taxing three hour and one minute runtime of “Endgame” limits the screenings each day, making it all the more challenging.

The most money that the entire domestic box office has ever generated in a single weekend is $314 million, according to Comscore. That came with the launch of “Avengers: Infinity War” in 2018 — and the superhero sequel accounting for a record $257.7 million of that haul. The remaining movies showing that same weekend pulled in a combined $56 million. The second-biggest industry weekend was $313 million, when “Star Wars: The Force Awakens” debuted in 2015 with $247 million. If “Avengers: Endgame” were to make $300 million alone, it would mean that nearly every other film that’s currently in theaters would barely attract any audience at all. Of course, there aren’t many new offerings on the marquee since studios steered clear of releasing a movie that could get crushed by the superhero tentpole. But assuming theaters are still allocating at least some screens to films that aren’t Marvel related, the domestic box office would have to reach unparalleled heights.

“For one movie to do $300 million would be unprecedented,” said Paul Dergarabedian, a senior media analyst at Comscore. “The potential is there for a record, but I don’t even know if it’s possible.”

He added, “For some fans, this is the holy grail. That’s why we’re so caught up in this guessing game of how high the numbers can go for ‘Endgame.'”

If “Endgame” isn’t able to cross $300 million in its debut, it won’t be for lack of trying. The film will open in over 4,600 North American theaters this weekend, marking the widest release of any movie at the domestic box office. Premium formats such as Imax and 3D that cost more money than the average ticket could also boost numbers. Exhibitors are also working in overdrive to add as many showtimes as possible to keep up with sky-high demand. Some AMC locations will be open around the clock for 72 hours straight starting Thursday evening. (Extra points for the moviegoers who are wiling to book an 11:30 p.m. showing of the three-hour epic.)

“Avengers: Endgame” is still expected to surpass the all-time opening weekend record in North America, currently set by “Avengers: Infinity War.” “Endgame,” the culmination to the current phase of Marvel movies, could debut to over $800 million worldwide since it opens day and date in almost every major territory. “Infinity War” also holds the record for the biggest global launch with $640 million, and that wasn’t including China. “Fate of the Furious” still has the best international launch with $443 million, but “Endgame” looks to crush that figure since its bounty will include the Middle Kingdom.

Anthony and Joe Russo directed “Avengers: Endgame.” The film picks up after “Avengers: Infinity War” and sees Iron Man (Robert Downey Jr.), Black Widow (Scarlett Johansson), Captain America (Chris Evans), the Hulk (Mark Ruffalo), Captain Marvel (Brie Larson), Thor (Chris Hemsworth), and Ant-Man (Paul Rudd), and the remaining Avengers scrambling to save the universe after a marbled villain named Thanos wipes out half of life in the galaxy.