Coelacanths have been around for more than 400 million years, can grow to more than 2 meters in length, and weigh up to 200 pounds. Today they are considered living fossils, according to Kevin Swagel, assistant collections manager in the Fish Division of the Field Museum in Chicago. Swagel unboxed one of the museum’s three coelacanths to reveal the preservation process.

In the video above, Atlas Obscura learned how the museum preserves its delicate wet specimens.

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