Dungeons & Dragons is a structured yet open-ended role-playing game. It is normally played indoors with the participants seated around a tabletop. Typically, each player controls only a single character, which represents an individual in a fictional setting. When working together as a group, these player characters (PCs) are often described as a "party" of adventurers, with each member often having their own area of specialty which contributes to the success of the whole. During the course of play, each player directs the actions of their character and their interactions with other characters in the game. This activity is performed through the verbal impersonation of the characters by the players, while employing a variety of social and other useful cognitive skills, such as logic, basic mathematics and imagination. A game often continues over a series of meetings to complete a single adventure, and longer into a series of related gaming adventures, called a "campaign".