SimTower: The Vertical Empire (known as The Tower in Japan) is a construction and management simulation video game developed by OpenBook Co., Ltd. and published by Maxis for the Microsoft Windows and Macintosh System 7 operating systems in November 1994. In Japan, it was published by OpenBook that same year and was later released for the Sega Saturn and Sony PlayStation in 1996. The game allows players to build and manage a tower and decide what facilities to place in it, in order to ultimately build a five-star tower. Random events take place during play, such as terrorist acts that the player must respond to immediately.