A carillon is a keyboard percussion instrument composed of a range of bells controlled by a keyboard. Carillons are normally housed in towers and are among the largest musical instruments in the world.
Carillons originated in the 15th century in Flanders, when bell-makers perfected their art to the point where bells could be cast with an exact tone. The greatest concentration of antique carillons is still found in Belgium, the Netherlands, and the northern regions of Germany and Poland, where they were commonly put in place by rich market towns as tokens of civic pride and status.
They were most often housed in church towers, clock towers, or on municipal buildings, and the same holds true for those carillons that have been installed in other parts of the world since the art of casting precisely tuned bells was rediscovered in the late 19th century. In Germany, such a carillon is also called a glockenspiel.
Since each separate note is produced by an individual bell, a carillon's musical range is determined by the number of bells it has. With fewer than 23 (two octaves), the instrument is considered a chime, not a true carillon. Average instruments have ranges of around four and a half octaves (47 bells), while the largest specimens, with as many as 77, can span six octaves. In comparison, standard grand pianos can play 88 different notes.
Seated in a cabin beneath the bells, the carillonneur presses down, with a cupped hand or fist, on a series of baton-like keys arranged in the same pattern as a piano keyboard. The keys activate levers and wires that connect directly to the bells' clappers; thus, as with a piano, the carillonneur can vary the intensity of the note according to the force applied to the key. In addition to the manual keys, the heavier bells are also connected to a series of pedals, offering the carillonneur a choice of two ways of playing the lower notes.
Noted carillons can be found in the following locations:
- Arlington, Virginia: The Netherlands Carillon. A 50-bell gift from the people of the Netherlands, with bells cast by all three major Dutch foundries.
- Richmond, Virginia: The World War I Memorial Carillon. A 56-bell carillon tower.
- Mexico City: The Banobras Carillon. A 47-bell instrument in the world's tallest carillon tower (125 m), which is part of a Mexican government development bank office complex in the Tlatelolco district.
- Montreal, Quebec: The Carillon of St. Joseph's Oratory. A 56-bell carillon installed in 1956.
- New Haven, Connecticut: Harkness Carillon in Harkness Tower at Yale University: 10 bells (a chime) installed in 1922, and an additional 44 bells installed in 1964, for a total of 54 bells.
- Berkeley, California: Berkeley Carillon in Sather Tower at University of California, Berkeley: 12 bells (a chime) installed in 1917, an additional 49 bells installed in 1978 and 1982, for a total of 61 bells.
- Norwood, Massachusetts: The Walter F. Tilton Carillon, in the Norwood Memorial Municipal Building. A 51-bell instrument made by Gillette and Johnston, with bells ranging in size from 6½" to 71" (16.5 to 180 cm).
- Ottawa, Canada: The Peace Tower Carillon, in the Houses of Parliament,. 53 bells.
- Austin, Texas: The Main Building Tower, at the The University of Texas at Austin, with 56 bells.
- Ann Arbor, Michigan: Charles Baird Carillon, housed in the Burton Memorial Tower at the University of Michigan. Claims to be tied for the 4th heaviest carillon in the world (43 Tons). 55 bells.  (http://www.umich.edu/~urecord/0102/Nov05_01/18.htm)
Also of note:
- Frank DellaPenna, founder of Cast in Bronze (http://www.castinbronze.com), is a notable carillon performer. His 35_bell instrument is particularly rare in that it is one of the very few travelling carillons that exist in the world.