Sonic Adventure (ソニックアドベンチャー Sonikku Adobenchā?) is a platform video game developed by Sonic Team and published by Sega. It was originally released for the Dreamcast as a launch title in Japan in 1998, and worldwide in 1999. It was the first game in the main Sonic the Hedgehog series since Sonic & Knuckles in 1994, and was the best-selling game on the Dreamcast.