Satan has escaped from hell and is spying out Eden to find opportunity to deceive Eve. Beginning at Book IX Line 444:
Almost as if to compare cities to hell and rural country to eden. I'm not saying that's correct, I'm just saying. :-)
"Much he the place admir'd, the person more.
As one who long in populous city pent,
Where houses thick and sewers annoy the air.
Forth issuing on a summer's morn, to breathe
Among the pleasant villages and farms
Adjoin'd, from each thing met conceives delight;
The smell of grain, or tedded grass, or kine,
Or dairy, each rural sight, each rural sound; "