The Analytical Engine
Before the current, there was the intention.
Charles Babbage drew a machine of brass and steam — a store to hold numbers, a mill to work them, and a ribbon of punched cards to tell it what to do. It was never finished while he lived.
Ada Lovelace saw past the metal. She wrote the first algorithm for it, and the century's first real idea: that a machine might one day work not only numbers, but anything at all we can learn to encode.