See, between 1940 and 1970, several colleges -- including Harvard, Yale, Vassar, and Brown -- required first-year students to pose au naturel for several photographs. No, it wasn't for some creepy Skull-and-Bones-esque secret society, although it was bone-related. These photos formed part of a massive study undertaken by psychology researcher William Herbert Sheldon into how rickets develops. This involved sticking metal pins to the students' backs:
The New York Times
It's since been suggested that the study was actually focused on proving the pseudoscientific principle (also believed by people like, uh, the Nazis) that analyzing a person's body can yield a whole bunch of information about their intelligence, moral worth, and "probable future achievement." We don't know that for sure, but we do know that Sheldon used the photographs to identify three distinct body types: skinny, nervous "ectomorphs," fat and jolly "endomorphs," and confident, buff "mesomorphs." Was he secretly conducting a study on the scientific validity of The Three Stooges?
Whatever the case, the most tangible result of the study was that a whole generation grew up terrified of their nudes leaking one day -- something millennials know nothing about. A lot of the photos were burned after the study was denounced, but others could still be out there, being eagerly traded by people with porcupine fetishes.