Of all the props and items that show up in the Marvel Cinematic Universe, few are as iconic as Mjölnir, the enchanted hammer of Thor. The weapon has been at the hero's side since his 2011 cinematic debut, smiting enemies, summoning thunder and flying wherever he sends it, at least until Hela destroyed it last year in Thor: Ragnarok.

For all of Mjölnir's significance, it has a deceptively simple design, but it's one that formed one of the building blocks for the early MCU. Charlie Wen, the former head of visual development for Marvel Studios, has revealed 25 designs for the hammer, accompanied by his memories of developing the look and feel for Thor and his world.

The images show a variety of potential hammers, ranging from the squared-off bludgeon that became the final design to much more intricate and mystical-looking weapons. "The first image is the initial pass that goes from more traditional to wacky," Wen explained on Instagram. "The purpose was to begin establishing with Kevin [Feige]a sense of boundaries and comfort levels for the magical realms of the MCU (in comparison to the earthly ground of Iron Man’s tech)." The next pages of concept art feature a series of hammers taking on a vibrant glow and then becoming enveloped in lightning.

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Wen also provided some insight into the early production process of the films, and its scheduling demands: "I was supposed to have a long lead time to develop the look and feel of the Avengers world years before production, which would have been incredible to have that kind of time- but I was pulled into developing the look and feel of Thor’s world first as it needed help."

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In addition to the need for the design of Asgard to come first, there was a necessity for Mjölnir to be the first thing from Asgard to be designed. The toy company Hasbro was planning its toy line and needed to begin production, so Wen got to work on Thor's hammer, ensuring that any replica would be faithful to the film.

Although Thor has a new weapon as of Avengers: Infinity War, Mjölnir has had an impact on the MCU, so it can't be denied that the visual development team's hard work paid off. "It’s always necessary to go too far!" Wen said about his early designs. "In these stages, I found it paramount to begin designing the MCU as a cohesive universe."