Holy smokes! That would bring a lot of people to mass for sure!

The Botafumeiro is a famous thurible found in the Santiago de Compostela Cathedral (in the past similar devices were used in large churches in Galicia, nowadays sometimes is used in the Tui Cathedral). Incense is burned in this swinging metal container, or "incensory". The name "Botafumeiro" means "smoke expeller" in Galician

The Botafumeiro is suspended from a pulley mechanism in the dome on the roof of the church . The current pulley mechanism was installed in 1604.

The present Botafumeiro is made of an alloy of brass and bronze and is plated by a very thin 20 micrometre layer of silver. The current Botafumeiro was created by the gold and silversmith José Losada in 1851. 

That bad boy getting ready to rock!

I'm surprised this thing hasn't tagged a priest or penitent yet ( or maybe it has! ).

Shovels are used to fill the Botafumeiro, or the Alcachofa, with about 40 kg of charcoal and incense.^[11] The thurible is tied to the rope with elaborate knots. The censer is pushed initially to start its motion. Eight red-robed tiraboleiros pull the ropes, producing increasingly large oscillations of the censer. The turible's swings almost reach the ceiling of the transept. The incensory can reach speeds of 68 km/h as it dispenses thick clouds of incense.

At the top of the swing, the Botafumeiro reaches heights of 21 meters. It swings in a 65 meter arc between the Azabachería and Praterias doorways at the ends of the transept. The maximum angle achieved is about 82°. The maximum can be reached after about 17 cycles, and requires about 80 seconds of swinging.

It costs about 250€ for each thurible "performance" at the cathedral. Although this is expensive, the swinging of the thurible is very popular with pilgrims, tourists and visitors.