such as signals and ship camouflage. The game features combat missions, challenges, campaigns and collections for the sake of creating extra goals, rewards and a meaningful progression for players during their time with the game. These systems also give an opportunity of creating stories inside or outside the military or historical genres. Some special Halloween, April Fools, and other holiday battle modes appear in the game. The secondary goal of the "holiday modes" is to test new game mechanics. Temporary anime tie-in events have occurred, featuring ships and characters (as ship commanders) from High School Fleet, Azur Lane, and Arpeggio of Blue Steel. Other events have used science-fiction-themed ships and environments, but not tied to a specific franchise. Battles take place on a limited number of specific maps, each depicting a certain location with different geographical layouts, usually featuring numerous islands of varying size that influence play. Most maps have a static or dynamic weather system to make battles more diverse. Moreover, some maps are unique for a certain game mode, e.g. PvE scenario battles based on historical events such as the Dunkirk evacuation. Scenarios is a PvE game mode where players cooperate and complete tasks. They include a number of operations, each with separate stories, objectives, secondary objectives and rewards. Tasks include not only destroying enemy vessels but also bombarding shore installations, escorting convoys, or preventing enemy vessels from entering or escaping certain areas. To finish the scenario, players need to team up and complete the primary objective. On completion of the secondary objectives, they receive an additional star. In addition to Ranked Battles, Clan battles were introduced as another competitive mode that is played in the season format. Players can only participate in Clan Battles as a team, as opposed to Ranked battles where individual players compete against each other. A clan is a group of "teamed" players who either apply or are invited. Also, a bonus resource, oil, can be awarded and contributed to the clan. The commanders (owners) of the group can use this to build and upgrade fleet buildings, which give bonuses to every player in the clan. Release On August 16, 2011, the company website of Wargaming, developer and publisher of World of Tanks and World of Warplanes, announced World of Battleships, a free-to-play naval action MMO, intended to complete the World of war trilogy developed by the company. On August 2, 2012, the