10 Highest Ever Grossing Movies Released In May - Ranked From Worst To Best

4. Iron Man

Domestic Gross: $318,412,101 Iron Man, the first and still arguably best movie in the MCU, blew movie-goers away when it introduced them to Tony Stark, who - embodied by the wonderful Robert Downey Jr. - became a cultural phenomenon off the back of a single film alone. Though Jon Favreau's competent direction certainly helped the movie towards success, this really is The Robert Downey Show from start to finish. His performance cemented Tony Stark as the best and most popular hero in the entire MCU canon; it's no wonder his turn here relaunched his whole career. Still, there are other reasons as to why Iron Man is such a great movie - free from the constructs and restrictions brought on by being a later-stage MCU movie, there's more room to explore Tony as a character without getting bogged down in other matters. Had Iron Man not been quite so successful both at the box office and with audiences, it's entirely possible that Marvel would've given up on the idea of a shared universe. To think, comic book fans initially resisted the casting of Robert Downey Jr. as Stark; Robert Downey Jr. is freakin' Iron Man!