Grand Theft Auto is a long-running series of video games, published by Rockstar Games and developed by subsidiary companies. The games allow the player to take on the role of a criminal in a big city, typically an individual who rises through the ranks of organised crime through the course of the game. Various missions are set for completion by the figureheads of the city underworld, generally criminal, which must be completed to progress through the storyline. Assassinations, and other crimes feature regularly, but occasionally taxi driving, firefighting, pimping, street racing, or learning to fly fixed-wing aircraft are also involved as alternate adventures, which can be done at any time during the game.