Spasim

Spasim (abbreviation of "space simulation") was a 32-player 3D networked computer game by Jim Bowery involving 4 planetary systems with up to 8 players per planetary system, released in March 1, 1974. Jim Bowery claims that it is the very first 3D multiplayer game and has offered reward of US $500 to anyone who could document an example of a multiplayer 3D virtual reality game prior to Spasim. In Spasim the players flew around in space and to each other as they appeared as wire-frame space ships. Their positions were updated about every second. The game was played on the PLATO computer system.

Source: Wikipedia, "[en.wikipedia.org/wiki/Spasim Spasim]", available under the CC-BY-SA License.