Water covers two-thirds of the earth’s surface, and makes up almost the same proportion of the human body. No living thing, from the giant squid to the cactus pot plant, the African elephant to the amoeba, can survive without it. It’s fitting, then, that Our Lord instituted water as essential to baptism, and so to membership of the Church: “No one can enter the kingdom of God without being born of water and Spirit.”

But the uses of water don’t stop there. Once blessed by a priest, it becomes holy water. (Some priests, it’s worth saying, believe it’s more effective to use the traditional ritual, including an exorcism of the water.) There’s usually some at the entrance to a church; some Catholics carry it around or keep it at home.