The current record holder for biggest domestic opening belongs to last year's 'Avengers: Infinity War' with $257.7 million, followed by 'Star Wars: The Force Awakens' with $$248 million, unadjusted for inflation.


Let the bidding begin.


With less than three weeks left to go, there's a fierce debate underway as to whether Disney and Marvel's Avengers: Endgame can crack the $300 million threshold at the domestic box office and $800 million to $900 million globally — a record on both fronts.


Endgame is a climax of sorts to the 21 previous titles in the Marvel Cinematic Universe, a blockbusters series of film that commenced with the breakout hit Iron Man in 2008 and established Kevin Feige's Marvel Studios as the best in the show.


The tentpole is a direct sequel to Avengers: Infinity War, which opened to $257.6 million in late April 2018, marking the biggest North American launch of all time ahead of Disney and Lucasfilm's Star Wars: The Force Awakens ($248 million).


Globally, Infinity War launched to a record-shattering $640.5 million. That was without China, where it opened two weeks later to a massive $359 million.


The big question mark — Endgame runs 3 hours and 1 minute, the longest of any MCU title and meaning one fewer showtime a day, on average (Infinity War was 2 hours and 29 minutes).


Disney and Marvel can make up the difference by booking even more screens for the superhero extravaganza, directed by the Russo brothers.


So far, early tracking shows Avengers: Endgame debuting domestically to $200 million to $250 million. However, when the movie sold more advance tickets in its first 24 hours than any pic history, the speculation spiraled. Box office sources said they believe a realistic range is $250 million to $280 million.


Adds Paul Dergarabedian of ComScore, "like some sort of box office unicorn, the opening weekend speculation surrounding Endgame has taken on mythical proportions. No matter the actual number, the fact that people are putting this crazy $300 million number into the ether shows how much enthusiasm and excitement there is for what is arguably the most anticipated Marvel movie ever."


Tracking in hardly a science, When Infinity War first came up on track, it was tipped for a debut of $185 million to $225 million.


One potential competitor for Endgame will be the third episode for HBO'S Game of Thrones, which airs on Sunday nights.


"The weekend of April 26 for many people will be like having the Super Bowl, the Oscars and their Birthday all on the same weekend," says Dergarabedian, "Fortunately for Avengers and GOT fans, there is more than enough time to enjoy both."