he world of Mozart Mud is a large and diverse place filled with many strange regions, each containing its own kind of inhabitants with their different treasures. The world is divided into two realms—the Surface, where elves, humans, dwarves and many other races dwell beneath the light of the sun and moon, and the Underdark, where the drow rule supreme and the light of the sky does not penetrate. Each realm is in turn divided into many areas or zones, and each zone is divided into many rooms. A room is the smallest unit of area—analogous to a "square" or "tile" in a board game, although not all rooms are square in shape—linked to adjacent rooms by its exits.

urrently, the world of Mozart Mud boasts over 28,000 rooms: slightly less than 5,000 of these are in the Underdark and the rest are on the Surface. These are grouped into some 200 zones containing various monsters and items. Mozart Mud's area listings give each zone a level range: this is the suggested range of ability for characters to hunt (relatively) safely in that zone, facing foes of reasonably equal ability, and is not intended to be perfect—the most powerful monsters in a particular zone may in some cases be beyond the ability of a single character of the maximum suggested level to defeat. Some creatures in the world may be beyond the power of almost anyone to defeat alone, thus encouraging grouping and teamwork.

Each zone has a reset frequency—the length of the interval between resets of the zone which restore all its inhabitants to life. Each time a zone resets, each object that may be found within it has a percentage chance of appear. The base percentage chance is set on the object during the area's creation and may vary greatly between objects even within a single zone; at each zone reset, the base chance is scaled according to the number of players currently online, so that the approximate number of items will stay in sync with the number of players. As a general rule of thumb, the more powerful the object, the less frequently it will appear.