Post offices are buildings where letters and packages can be sent and received. They may be located in towns or cities. Fictional post offices may use animal such as ravens, owls, sprites, mini-dragons, or robots to deliver the mail. In game-oriented worlds post offices may be places where players can send messages to one another or receive quests involving the delivery of a piece of mail or package. Post offices may have extensive conveyor systems in their back rooms to help sort the mail.