Ode on a Grecian Urn

Thou still unravish’d bride of quietness,
    Thou foster-child of silence and slow time,
Sylvan historian, who canst thus express
    A flowery tale more sweetly than our rhyme:
What leaf-fring’d legend haunt about thy shape
    Of deities or mortals, or of both,
        In Tempe or the dales of Arcady?
    What men or gods are these?  What maidens loth?
What mad pursuit?  What struggle to escape?
        What pipes and timbrels?  What wild ecstasy?
                                                                Ode on a Grecian Urn— John Keats

So what are the two best known lines of this poem?