A tower which contains one or more bells, or which is obviously designed to hold bells (even if it has none), is a bell tower. Most commonly, it is part of a church; but when attached to a city hall or other civic building (especially in continental Europe), it is often named belfry. (Elsewhere, the term "belfry" refers strictly to the part of the tower which contains the bells. Thus some bell towers have no belfry.) The occasional free standing bell tower may also be referred to by its Italian name, campanile. Old bell towers may be kept for their historic or iconic value, though in countries with a strong campanological tradition they often continue to serve their original purposes as well; a few new towers are built every year for similar reasons.
Bell towers may also contain carillons or chimes, musical instruments traditionally composed of large bells which are sounded by cables, chains, or cords connected to a keyboard. These can be found in many churches in Europe and America and at some college and university campuses. In modern constructions that do not qualify as carillons, rather than using heavy bells the sound may be produced by the striking of small metal rods whose vibrations are amplified electronically and sounded through loudspeakers. Simulated carillon systems have also used recordings or samplings of bells onto tape, compact disc, or memory chips.
In 1999 thirty-two Belgian belfries were added to the UNESCO's list of World Heritage Sites. In 2005 this list was extended with one Belgian and twenty-three French belfries and is since known as Belfries of Belgium and France. Most of these were attached to civil buildings, mainly city halls, as symbols of the greater power the cities in the region got in the Middle Ages; a small number of buildings not connected with a belfry, such as bell towers of—or with their—churches, occur also on this same list (details).