Arkham Horror is an adventure board game designed by Richard Launius, originally published in 1987 by Chaosium. The game is based on Chaosium's roleplaying game Call of Cthulhu, which is set in the Cthulhu Mythos of H.P. Lovecraft and other horror writers. It was revised and reprinted by Fantasy Flight Games in 2005. In this game, players take on the role of investigators in Lovecraft's Massachusetts town of Arkham. Gates to other planes open throughout the town. If too many gates open, a powerful alien being will enter, likely destroying the town and possibly threatening the world. The investigators must avoid or fight alien creatures that enter Arkham through the gates, enter the gates themselves, survive the alien places beyond, return to Arkham, and close the gates.