The Santiago de Compostela botafumeiro (“smoke expeller”) is the largest censer/thurible in the world. Created by silversmith José Losada in 1851, it is usually on display in the library of the Cathedral of Santiago de Compostela (in Santiago, Galicia, Spain). But on holy days, it is loaded with charcoal and incense, fired up, attached to a pulley and eight tiraboleiros pull the ropes and swing the censer back and forth, almost to the roof of the transept, dispensing thick clouds of incense smoke.
The use of a swinging censer in this cathedral dates from the 11th century, and it is said the practice originally helped to mask the aroma of hundreds of unwashed pilgrims. (It is believed the remains of the apostle James are in a reliquary beneath the high altar, and hence the cathedral has for centuries been the destination of the “Way of St. James” pilgrimage.)
Incense burning is, of course, an important part of the liturgy, a symbol of prayers rising to the heavens. The swinging censer at Santiago de Compostela is popular to this day, but has not always been free of misadventure. During a visit by Princess Catherine of Aragon in 1499, the swinging botafumeiro came loose and flew out of the cathedral through a high window.