Minaret: a slender tower, typically part of a mosque, with a balcony from which a muezzin calls Muslims to prayer. Chapel: a small building or room used for Christian worship in a school, prison, hospital, or large private house. Belfry: the part of a bell tower or steeple in which bells are housed. Spire: a tapering conical or pyramidal structure on the top of a building, typically a church tower.