A bell tower is a tower that contains one or more bells, or that is designed to hold bells even if it has none. Such a tower commonly serves as part of a Christian church, and will contain church bells, but there are also many secular bell towers, often part of a municipal building, an educational establishment, or a tower built specifically to house a carillon. Church bell towers often incorporate clocks, and secular towers usually do, as a public service.
The term campanile (ˌkæmpəˈniːli,_-leɪ, also USˌkɑːm-, kampaˈniːle), from the Italian campanile, which in turn derives from campana, meaning "bell", is synonymous with bell tower; though in English usage campanile tends to be used to refer to a free standing bell tower. A bell tower may also in some traditions be called a belfry, though this term may also refer specifically to the substructure that houses the bells and the ringers rather than the complete tower.
The tallest free-standing bell tower in the world, high, is the Mortegliano Bell Tower, in the Friuli Venezia Giulia region, Italy.
File:Elizabeth Tower 2014-09-21 205MP.jpg|[[Elizabeth Tower]], [[London]] completed in 1859; better known as [[Big Ben]].
File:Italy - Pisa - Leaning Tower.jpg|The [[Leaning Tower of Pisa]], campanile of the [[Duomo di Pisa]], Italy
File:Venezia - Panorama 010, Campanile San Marco.jpg|[[St Mark's Campanile]], [[Venice]]
Bells are rung from a tower to enable them to be heard at a distance. Church bells can signify the time for worshippers to go to church for a communal service, and can be an indication of the fixed times of daily Christian prayer, called the canonical hours, which number seven and are contained in breviaries. They are also rung on special occasions such as a wedding, or a funeral service. In some religious traditions they are used within the liturgy of the church service to signify to people that a particular part of the service has been reached.
A bell tower may have a single bell, or a collection of bells which are tuned to a common scale.