In 1977 the first multi-user or multi-player computer games, or MUDs began to evolve on the PLATO system at the University of Illinois, Urbana-Champaign. The PLATO MUDs ran on a bulletin board system or Internet server and combined "elements of role-playing games, hack and slash style computer games, and social chat rooms."
"Numerous dungeon crawlers were created on the PLATO system at the University of Illinois and other American universities that used PLATO, beginning in 1975. Among them were "pedit5", "oubliette", "moria", "avatar", "krozair", "dungeon", "dnd", "crypt", and "drygulch". By 1978-79, these games were heavily in use on various PLATO systems, and exhibited a marked increase in sophistication in terms of 3D graphics, storytelling, user involvement, team play, and depth of objects and monsters in the dungeons."