Tomb Raider
Though not the first 3D action/adventure game to hit the market it was one of the earliest and probably the one the most served to popularize the genre (along with Super Mario 64 of course). Development of Tomb Raider started in 1993 and the game was released in 1996 to glowing reviews and enormous sales. Approximately 7.5 million copies of the original game were sold across all platforms. The game was originally released for the PC (DOS), PlayStation and Sega Saturn though there have been a number of re-releases, remakes and sequels for various platforms since.