The media juggernaut that is the Marvel Cinematic Universe (MCU) had humble beginnings in a 1961 comic book created by writer Stan Lee and artist Jack Kirby – the first issue of Fantastic Four.
In bygone days, it was common for superheroes to be placed in life threatening situations with readers being confident that the hero would somehow escape the clutches of death. But that concept was first challenged in X-Men #137 (1980) when Jean Grey (aka Marvel Girl/Phoenix) took her own life in order to protect the universe from the Phoenix force that possessed her. In an unforgettable sequence, Jean Grey paid the ultimate price in order to save the universe.