Karakura CityThis is the City where everything began,
The city resembles modern Japan, Tokyo, to be more precise.
It is hometown and residence to most major characters and it is the place where all the main characters go to school.
Nevertheless it doesn't seem to be an extraordinary huge city, having rather an average number of Inhabitants. However, quite a lot of inhabitans seem to have special spiritual abilities. After all it is also the city Aizen tries to destroy in order to get a second royal key.
Soul Society:Soul Society is home to many souls and to the Shinigami. It consists of North, South, East and West Rukon which are devided in eighty cantons. The higher the number is, the more dangerous the area is. Another important part not belonging to the cantons is Seireitei. Seireitei is the district where the Shinigami live and work. The base of the Soul Reapers is situated in Seireitei as well.
Most Shinigami live in one of the Rukon Districts before they attend Academy.
Hueco Mundo:Hueco Mundo is where the Hollows live. It is the kingdom of Aizen and lies between the Soul Society and our world. The name is of spanish origin and bears the meaning of "empty world". It is a dimension between the human world and Soul Society. The Hollows are undetectable as long as they remain in Hueco Mundo.
In Hueco Mundo it is night all the time, why it is like that hasn't been explained till now. The air consists of Spirit Particles, of which the Hollows feed themself. There is no water in Hueco Mundo, Even the animals living there are Hollows, although smaller than the normal Hollows. The ground is completely covered with sand and everything is white, which is the reason the Hueco Mundo occurs quite dimly and dreary. There are few trees to see, which belong to the Menos Forest growing below the Hueco Mundo. Alrhough it is called forest, it isn't a forest at all, but the nest of Hollows, where all Hollows are given birth to.