how about SimAnt or SimEarth?!
both crap games....
a good one that IS still the the biggest world to date is DaggerFall
As of May 2010, Daggerfall is the largest explorable game world to date,[1] featuring a game world estimated as being 62,394 square miles (161,600 square kilometers or about 40 million acres) with over 15,000 towns, cities, villages, and dungeons for the player's character to explore. However, Bethesda claims an even bigger land mass of twice the size of Great Britain[2] (would be around 487000 square kilometers). According to Todd Howard, Elder Scrolls programmer, the game's sequel, The Elder Scrolls III: Morrowind is 0.01% the size of Daggerfall, but it should be noted most of Daggerfall's terrain was randomly generated. Vvardenfell, the explorable part of Morrowind in the third game has 10 square miles (25.9 square kilometers).[3][4] The Elder Scrolls IV: Oblivion has approximately 16 square miles (41.4 square kilometers) to explore.[5] In Daggerfall, there are 750,000+ non-player characters (NPCs) for the player to interact with, compared to the count of around 1000 NPCs found in Morrowind and Oblivion. However, the geography and the characters in these later games are much more detailed.
In Daggerfall, as in all The Elder Scrolls games, players are not required to follow questlines or fill specific character archetypes.
Daggerfall features a spell creation system where, through the Mages Guild, players can create custom spells with several different effects. The game will then automatically generate the mana cost of the spell based on the power of the effects chosen.
Other features include an equipment enchantment system (similar in concept to the spell creation system), the ability to buy houses and ships, a variety of clothing and equipment, dynamic political relationships between kingdoms, the ability to become a vampire, werewolf, or wereboar, and the combat system, which uses mouse movement to determine the direction and effect of weapon swings in melee combat.
The political system is supported by a net of Guilds, orders, and religions, all with unique tasks and quests. Joining and contributing to these facilities allows the player to raise ranks and achieve higher reputation in the game world, which affects how NPCs and other factions view the player.
Daggerfall has genre-typical gore elements and some sexual topics. It displays cartoonish nudity (showing breasts but no genitals) both on NPCs and on the character's paper doll when all equipment is removed. The game installer includes a password-protected childgard feature that hides blood and corpses (instead showing just the skeleton of the corpse), disables sexual topics (though not removing all nudity), and ensures the character portrait is wearing underwear at all times.
