Growing up, Cathedrals were always presented to me as being a huge wastes of money and energy. Nothing but monuments too Roman Catholic excess. Much better were our utilitarian Baptist house of worship (which apparently strived to be the most boring structure in town.) I remember being filled with awe when I first visited the National Cathederal in D.C. I remember clearly the beautiful moon window. The first thought that came to my mind was how amazing God was, not how amazing man was for building the thing. N.T. Wright, who served as the Anglican Bishop at Lichfield Cathedral in England for a time, argues for their existence in his book on worship:

From For All God’s Worth
(p. 14)

The true God is the one who became human and died and rose again in order to offer a new way of being human, a way of worship and love. Christ died, says Paul, so that we might embody the saving faithfulness of God: “It is all God’s work.”Now if that isn’t true, a building like a cathedral is simply an expensive monument to an impossible dream; and all we do in it is simply an elaborate way of turning over in bed, the better to continue the dream rather than wake up and face reality. But if it is true-if it really is the case that the true God is the one whose love overwhelms us in Jesus Christ-then the appropriate response is celebration, because this God is the reconciler, the healer. Celebration and healing: that is what a cathedral is all about.

…So it isn’t surprising that those who are grasped by this gospel have built cathedrals. People who have forgotten who God is produce concrete jungles and cardboard cities. People who remember or rediscover who God is build cathedrals to his glory, and homes where the poor are cared for.