There was only one in the world and it was this one, the ENIAC. It was run by a team of 6 women who had to literally invent programing. The guys who built it gave them full schematics and said "you can ask the engineers any questions, here's the diagrams, make it work". Seriously.
They programed ENIAC by manually connecting inputs to outputs. Like, instead of code telling this parcel of information to "go here, do this calculation, then the result should head over there", the electricity just flowed and wherever the cables led the information went.
Imagine an entire stage packed full of oscillators and modular synths for an electronic artist, with wires manically being pulled and pushed into different components and the vigorous turnings of knobs. Like that, except with AC, spinny skirts, sensible pulling and pushing of cables, delicate and exact knob turning, and levels of pencil biting only a half dozen mathematicians can achieve.
They had to manually reconfigure every input-output pair each time they wanted to run a new program. They are responsible for many of the fundamental aspects of computer programing that are still around to this day.
After the 1940s all but two of these amazing mathematician-turned-programmers went home to cook, clean, and start families. They got zero credit for the amazing contribution to modern society they all made.
For 40 years no one knew of their existence. They were noted in zero history books, plaques, textbooks, or the minds of anyone save those who worked on the project or knew them personally.
Then, one day in the 80s a college student asked about pictures of them holding parts of ENIAC and at work programming. There was no names, no explanation, nothing except a few pictures in an archive.
The answer the student received was "those are models they used to make the computer seem more interesting". After finding that answer insufficient the student dug into the paper records and interviewed people who worked on the project and found out what these women really did.
They are finally known about, though you rarely hear of them. Everyone reading my words should take a moment to mentally thank/pray for/sacrifice a chicken to Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Meltzer, Fran Bilas, and Ruth Lichterman.