Day 16 - The Botafumeiro

So...

This happened

(Friday September 26, after the 7:30pm mass in the Cathedral of Santiago de Compostella)

From Wikipedia

One tradition has it that the use of a swinging censer in the Santiago de Compostela Cathedral began in the 11th century. Arriving pilgrims were tired and unwashed. It was also believed that incense smoke had a prophylactic effect in the time of plagues and epidemics. Of course, incense burning is also an important part of the liturgy, being an "oration to God", or form of prayer.

Many other cathedrals had similar large thuribles at one time. However, most of the other cathedrals discontinued the use of their swinging censers over the years.