🚨Warning: There are MASSIVE spoilers for the entire Marvel Cinematic Universe below!🚨
1. First, Tom Holland improvised the moment when Peter says, "I don't wanna go" before he's turned to dust in Avengers: Infinity War. When Holland wants to make himself cry, he repeats a phrase over and over again, and that's what inspired this.
2. And Groot's final "I am Groot" line in Infinity War before he gets dusted is actually him saying "Dad" as he looks at Rocket for the last time.
3. Kevin Feige first told Robert Downey Jr. that Tony Stark would probably die in December 2015, which was around the time they were finishing Captain America: Civil War.
4. Meanwhile, Scarlett Johansson found out that Natasha would die in Avengers: Endgame before production began on Infinity War — she said it didn't feel real until she was standing on the Vormir set alongside Jeremy Renner.
5. Most of the cast found out they were filming Tony's funeral in Avengers: Endgame the day they arrived on the set. Sebastian Stan said that he was told they were filming a wedding and then realized that Downey was missing.
6. In Black Panther, when Killmonger defeats T'Challa and throws him over the cliff, cinematographer Rachel Morrison and the camera crew filmed the entire scene with handheld equipment, so they were in the water right beside Michael B. Jordan and Chadwick Boseman.
7. One of the most emotional moments for Jordan to film in Black Panther was when Killmonger reunites with his father in a dream sequence.
8. In Guardians of the Galaxy Vol. 2, the moment when Kraglin screams during Yondu's funeral was inspired by Max at the end of One Flew Over the Cuckoo's Nest.
9. In Spider-Man: Homecoming, when Spider-Man is trapped under a building, Holland was actually lying underneath real rubble and cement, so it was super heavy; he said it was the hardest scene to film in the entire movie.
10. In Captain America: The Winter Soldier, Hayley Atwell wore very little makeup for the scene when Steve visits Peggy, who has Alzheimer's, so the finished product was created digitally. An older actor performed the scene, mimicking Atwell's movements, and then the two performances were combined.
11. While filming Peggy's funeral in Captain America: Civil War, Chris Evans jokingly texted Atwell a picture of the funeral, saying, "You look pretty hot when you're old and dead."
12. Tom Hiddleston knew about Loki's death in Avengers: Infinity War before filming Thor: Ragnarok — he said that knowing this helped inform his entire performance in Ragnarok.
13. In Captain America: The Winter Soldier, the moment when Bucky gets his mind wiped was inspired by Han Solo being tortured by Darth Vader in Star Wars: The Empire Strikes Back.
14. In Guardians of the Galaxy, Laura Haddock, who played Meredith Quill, recorded the dialogue for the moment when Peter reads the letter from his mom in the back of a car — Chris Pratt actually listened to the recording while filming the scene.
15. The first scene Annette Bening filmed for Captain Marvel was actually the moment when Dr. Wendy Lawson dies after the plane crash.
16. Before coming up with the mid-credits scene when Hope, Hank, and Janet turn to dust and Scott is trapped in the Quantum Realm in Ant-Man and the Wasp, the filmmakers thought about hinting at Thanos and Infinity War in the backgrounds of scenes throughout the movie, but it didn't pack the emotional punch that they wanted.
17. The last scene Downey filmed as Iron Man was Tony's emotional last words — they even filmed this moment on a soundstage right next door to where Downey had his original screen test for Iron Man 12 years before.
18. Also, there was originally dialogue written for Tony in Avengers: Endgame when everyone is saying goodbye to him, but Downey was "adamant" that Tony didn't need to talk here because his fight was done.
19. And finally, "I love you 3,000" was actually a phrase that Downey's son used when he was growing up. Downey told the writers about it, and it eventually made it into Avengers: Endgame.
