Which was the first film of the Marvel Cinematic Universe, released in 2008?

Who played Tony Stark / Iron Man in the Marvel Cinematic Universe? Who played Captain America in the Marvel Cinematic Universe? Who played Thor in the Marvel Cinematic Universe? Who played Black Panther (T'Challa) in the Marvel Cinematic Universe? Who is the main villain of 'Avengers: Infinity War'? Which film became the highest-grossing film of all time in 2019, before 'Avatar' reclaimed the title in 2021? Who played Wonder Woman in the 2017 film? Who played Superman in 'Superman' (1978)?