Comic book fans are enjoying the Golden Age of superhero movies, as many of their favorite characters are finally being adapted for the big screen. Everything from Batman to The Inhumans is coming through the pipeline, meaning the filmmakers are truly exploring their libraries of characters. . Here are 10 Amazing Hidden Easter Eggs in Superhero Movies.

Spider-Man 2

Doctor Strange is making his way to theaters as part of the Marvel Cinematic Universe, but he’s been name-dropped in movies well before Disney got a hold of him. When the Daily Bugle staff is trying to coin a name for new villain Dr. Octopus, someone suggests Doctor Strange. J. Jonah Jameson says it’s catchy… but it’s unfortunately taken and can’t be used. It’s an obvious reference to the Sorcerer Supreme and suggests that Stephen Strange could have been around in Raimi’s universe. It would have been fun to see the duo team up, and hopefully that can still happen in the MCU.

The Dark Knight

Batman needs a new suit to increase his mobility, and Lucius Fox is happy to oblige. When showing Bruce Wayne the new armor, Fox remarks that it’ll leave the Caped Crusader more vulnerable to knives and gunfire. Bruce is most concerned about how it’ll hold up against dogs after encountering some early in the film, to which Fox replies it should do fine against cats. The joke is a sly nod towards famed Batman character Selina Kyle/Catwoman, who would be played by Anne Hathaway in the sequel, The Dark Knight Rises. Nolan must have been thinking ahead to the third installment.

X-Men: Days of Future Past

Quicksilver was the breakout star of this time traveling adventure and fans can’t wait to learn more about him in X-Men: Apocalypse. Fans could learn more about his parentage, which was hinted at in Days of Future Past. While with Magneto, Quicksilver notes that his mother once knew a man who could control metal, alluding to the characters’ comic book histories. In the comics, Quicksilver is actually the son of Magneto, so it’ll be interesting to see if that angle is explored in a future film. It seems like too large an element to ignore, so hopefully Bryan Singer found room for it in Apocalypse.

Iron Man 2

At the end of his second solo movie, Tony Stark learns from Nick Fury he’s not fit for the Avengers Initiative. But it’s what’s going on in the background that’s more interesting. There’s a map visible with certain spots highlighted, including one in Africa. That could very well be a reference to the fictional nation of Wakanda, home of Black Panther. Marvel is known for planning far in advance, so it wouldn’t be surprising if they were planting the seeds six years before the character first appeared in a film. There’s also a dot in the Atlantic Ocean, which could be for Namor, but he’s not showing up anytime soon.

 Iron Man

Well before Iron Man was an international movie star, he had his own cartoon show. When he brought Tony Stark to the big screen, Jon Favreau found a way to tip his hat to the animated version. While Rhodey has pilots tracking down Stark in the Iron Man suit, he gets a phone call from Tony. Rhodey’s ring tone is a midi version of the 1966 cartoon’s theme song, a fun little nod for fans that remember the series. It may not be the most obvious reference, but for those who watched the show or are longtime fans of the character, it was a nice way to bridge the adaptations.

The Amazing Spider-Man 2

For all their faults, the relationship between Peter Parker and Gwen Stacy was a strongpoint of the Amazing Spider-Man series. That’s what made Gwen’s death in the second film so heartbreaking. Though it was implied Gwen would perish long before the movie came out, Spidey fans knew what was going on the minute the clock tower showed up in the third act. The time shown, 1:21, is a nod to the comic, The Amazing Spider-Man #121, the issue in which Gwen died at the hands of the Green Goblin. As shocking as the scene was, attentive viewers still had plenty of time to prepare themselves.

Captain America: The First Avenger

As an All-American Brooklyn kid living through World War II, Steve Rogers is probably the only movie hero that hates Nazis more than Indiana Jones. Marvel has been selling that idea from the very beginning, having Cap punch Adolf Hitler in the face on the cover of the comic’s very first issue. Years later when the Star Spangled Man was brought to the big screen, the famous image was recreated during the propaganda montage as Steve tours the country in his costume. Even to those who never read the source material, the connection was easy to make.