The prolonged barrage engulfed Zero-One in the glow of a thousand suns. But unlike their former masters with their delicate flesh, the machines had little to fear of the bombs' radiation and heat. Thus did Zero-One's troops advance outwards in every direction. And one after another, mankind surrendered its territories. So the leaders of men conceived of their most desperate strategy yet. A final solution: the destruction of the sky.

-- The 2nd Renaissance (Part2), Animatrix