What is the most popular movie in history?
Probably the godfather
Most popular movie ever is unlikely, but this movie has definitely got a large number of viewers and is very, very popular. The HSM movies are so popular they have a three, but the fourth might cause problems because the cast is being changed and it will definitely become less popular with less viewers.
The Titanic is the most popular movie ever. Avatar seems to be extremely popular, and District 9 since both movies kept me on the edge of my seat This question is kind of vague. After all does it mean most watched or highest grossing or best reviewed? I don't know about best reviewed but the most watched movie ever is Casablanca and the highest grossing movie ever is Avatar.