In the early 1970s William Crowther worked for the high-tech R&D company BBN Technologies as part of a team developing the ARPAnet; a computer network predecessor to the Internet. Aside from being a highly skilled hacker Crowther enjoyed caving at that time. One cave he made repeat visits to was the Bedquilt section of Colossal Cave in the Flint Mammoth Cave system in Kentucky. Crowther had been mapping the cave and entered the data into a computer to create a model. After a divorce Crowther spent less time caving and more on a computer game project for his two daughters. He had recently been playing the new Dungeons and Dragons tabletop game which would serve as inspiration for the game.
Combining elements of the caving maps, a fantasy world, and the fact that the mainframe computer he was working on had no graphics, the resulting game was Adventure; the first text adventure game. The first version in 1976 was small and incomplete. It was openly shared on the mainframe network and later discovered by Don Woods, who greatly expanded the game.
Adventure became very popular and spawned the entire computer adventure game genre.