In Xanadu did Kubla Khan a stately pleasure-dome decree: Where Alph, the sacred river, ran through caverns measureless to man down to a sunless sea. So twice five miles of fertile ground with walls and towers were girdled round: And here were gardens bright with sinuous rills, where blossomed many an incense-bearing tree; and here were forests ancient as the hills, enfolding sunny spots of greenery.