Keats, as a Romantic poet, is undoubtedly famous for his description of natural beauty. One of the ways in which the descriptions of nature operate in this poem is the way that Keats creates a division between the earth where man dwells, which is characterised by suffering and pain, and the realm of the nightingale in the sky, which is described as being above the realm of humans in every way. Note the following description that establishes and explores this comparison:
And haply the Queen-Moon is on her throne,
Clustered around by all her starry Fays;
But here there is no light,
Save what from heaven is with the breezes blown
Through verdurous glooms and winding mossy ways.
Note how the moon is imaginatively described as an enthroned queen surrounded by fairy stars in all of their beauty. The earth, on the other hand, is described as gloomy, twisting, mossy and dark, a place where there is "no light." The "ecstasy" of the sound of the nightingale's song, therefore, is strongly compared to the sufferings of mortal existence. Even though the description of earth is much darker, it is still arguably sensuous in the way it creates in our minds labyrinthine paths of "mossy ways" enshrouded by trees and darkness.