When reading Keats' Ode to a Nightingale in college, I was struck by the poem's power, but particularly by the closing lines.
The poet hears the call of the nightingale in a solitary woods, and the sound seems to draw his soul out of his body in an exquisite way that suggests a beauty in final release, in the act of dying amid such perfection. And the hint that dying might be only an awakening into a different reality.
These are the last lines..

"Adieu! adieu! thy plaintive anthem fades   
Past the near meadows, over the still stream,   
    Up the hill-side; and now 'tis buried deep   
          In the next valley-glades:   
Was it a vision, or a waking dream?   
    Fled is that music:—do I wake or sleep? "