At the start of the game, the player is placed on the surface of a procedurally generated and virtually infinite game world. The world is divided into biomes ranging from deserts to jungles to snowfields. Players can walk across the terrain consisting of plains, mountains, forests, caves, and various water bodies. The in-game time system follows a day and night cycle, with one full cycle lasting 20 real-time minutes. Throughout the course of the game, players encounter various non-player characters known as mobs, including animals, villagers and hostile creatures. Non-hostile animals—such as cows, pigs, and chickens—can be hunted for food and crafting materials, and spawn in the daytime.
The game world is procedurally generated as players explore it, using a map seed which is obtained from the system clock at the time of world creation unless manually specified by the player. Although there are limits on movement up and down, Minecraft allows for an infinitely large game world to be generated on the horizontal plane, only running into technical problems when extremely distant locations are reached.