Box office insiders believe Avengers: Endgame could potentially top Avatar's worldwide haul. 1 / 8
Avatar, of course, remains the biggest movie of all-time with $2.7 billion worldwide. 2 / 8
That could change, though, when Avengers: Endgame opens next week. 3 / 8
Experts are all but certain $2 billion is a lock for Endgame. 4 / 8
However, like with Avatar, Endgame may benefit from continued repeat viewings. 5 / 8
Which could ultimately push its box office even higher. 6 / 8
Especially as this may be the final outing for some of our heroes. 7 / 8
Directed by Anthony and Joe Russo, Avengers: Endgame opens on April 26. 8 / 8