A church building or church house, often simply called a church, is a building used for Christian religious activities, particularly for Christian worship services. The term is often used by Christians to refer to the physical buildings where they worship, but it is sometimes used as an analogy to refer to buildings of other religions. In traditional Christian architecture, a church interior is often structured in the shape of a Christian cross. When viewed from plan view the vertical beam of the cross is represented by the center aisle and seating while the horizontal beam and junction of the cross is formed by the bema and altar.