Used to love this half of Yeats's poem, can't remember when I read it (A-Levels?). Anyway, here's the first half of The Second Coming -
' Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold;
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;
The best lack all conviction, while the worst
Are full of passionate intensity. '