You see two vertical spirals side-by-side, and you think "oh, DNA." That double helix shape is THAT recognizable in our society. Today.
But it took a lot of hard work from quite a few scientists to reach the discoveries that led to that knowledge.
Matthew Cobb lays out the story in his book Life's Greatest Secret: The Race to Crack the Genetic Code. His work on the history of science led him to the Exchange for this interview from 2015.