Ultima Online (UO) is a graphical massively multiplayer online role-playing game (MMORPG), released on 24 September 1997, by Orygin Systems. It was the first game of the genre to reach widespread popularity and has had immense influence on all later games of this type. Ultima Online is a fantasy role-playing game set in the Ultima universe. It is known for its extensive player versus player combat system. Since its release, it has added eight expansion packs, a booster pack, and dozens of free content updates. The release of Ultima Online: Kingdom Reborn in 2007 brought a new game engine with a newer visual experience. Ultima Online continued the tradition of previous Ultima games in many ways, but due to advancing technology and the simple fact that it was Origin's first persistent online game, there were many new game mechanics as well. Partially designed as a social and economic experiment, the game had to account for the widespread player interaction as well as deal with the long history of players feeling as if they were the center of attention, as had been the case in single-player games. New to both the developers and the players, a lot that was planned never happened, and a lot that was unexpected did, and many new game mechanics were integrated to compensate. The game began with a single world, with specific expansion packs adding additional territory and new worlds. Beginning with the first expansion (Ultima Online: The Second Age), the original world gained the "Lost Lands", with additional land, dungeons, creatures, and terrain. It was only by the second expansion that a second and separate world, Trammel, was introduced. This led the developers to distinguish the original world by making the environment more grim, and naming this world "Felucca".