Read it through once

Once, when you looked up and I saw you, I thought of the tower of Babel and of those who laboured there, adding stone to stone with a single voice, and in the end could not agree. You smiled as though at some remembered jest. 'Why do you laugh?' I said. 'Because one must laugh,' you answered. 'If one does not laugh, one must cry; and these things are so large that laughter seems better.'