That's the "Botafumeiro" or "Smoke Shooter" in the Cathedral at Santiago de Compostela.
It takes three guys to charge it and a team of about a dozen men to get it swinging. They pull on short ropes attached to the main cable, as the thurible reaches the end of its arc, and they can really get it going.
My daughter made the Camino (at least, the part in Spain) a couple of years ago, walking and staying in the hostels along the Camino. She arrived at the Cathedral on St. James's Feast Day -- and got to see the famous Botafumeiro in action.
You can see it here.
I gotta say, the Spaniards know how to do things RIGHT.