After “Avatar’s” impressive 10-year reign as box office champion, “Avengers: Endgame” has officially dethroned James Cameron’s sci-fi epic to become the biggest movie of all time. On Saturday, Disney and Marvel’s blockbuster crossed $2.7892 billion at the global box office. Once weekend ticket sales are tallied, the tentpole will exceed the $500,000 needed to surpass “Avatar’s” $2.7897 billion benchmark. “Avengers: Endgame” has amassed $853 million at the domestic box office, making it the second-highest grossing movie in North America behind “Star Wars: The Force Awakens” ($936 million). Internationally, it collected a mighty $1.9 billion, boasting especially strong performances in China...