The passing of beloved Marvel co-creator Stan Lee this past Monday sent a shock through the fandom. His comic books and contributions to the Marvel Cinematic Universe shot him to fame, as well as his frequent cameos in many of the much-loved installments of the franchise. Creating and overseeing characters such as the Fantastic Four, Spider-Man, the Incredible Hulk, Doctor Strange, the X-Men, Iron Man, Black Panther, Thor, Daredevil, and more, Lee changed the comic book industry as a whole.

Born Stanley Martin Leiber in 1922, in 1939 he began working at a company that would soon become Marvel Comics. Commissioned to create a comic book to compete with the Justice League in 1961, Lee and Jack Kirby co-created the Fantastic Four. Lee added real problems and pun-filled catchphrases to his characters that have since become staples in pop culture. His new characters made the switch from page to screen in the dozens following the release of the first Iron Man movie in 2008. Now the number of Marvel films is in the twenties, with new films scheduled for release within the year.

Stan Lee isn’t just recognized for his brilliant imagination, but also for his strong devotion to civil rights. Some of his comics, including Black Panther and X-Men, put his characters in the real world to fight off injustices such as racism during the Black Power movement of the 1960s. Not only did he write his superheroes with a yearning for justice, Lee himself fiercely spoke out against racism and bigotry. During the late 1960s, Lee turned “Stan’s Soapbox” into an anti-racism column that appeared in Marvel’s monthly new page, the “Bullpen Bulletins.” Although the bulletins were discontinued along with Lee’s column in 2001, he continued to speak out about “the deadliest social ills plaguing the world today.”

Fans, actors, and superheroes alike have taken to social media to remember him and celebrate his legacy. From Chris Evans, Robert Downey Jr., and Hugh Jackman to Jessica Alba, Elizabeth Banks, Tom Holland, and more, the actors who brought Lee’s imagination to the big and small screen paid their respects on Twitter and Instagram with photos and heartfelt messages.