What is the main idea in stanza 1

"Far enough down is China", somebody said.
"Dig deep enough and you might see the sky
as clear as the bottom of a well.
Except it would be real -- a different sky.
Then you could burrow down until you came
to China! Oh it's nothing like New Jersey.
There's people, trees, and houses, and all that,
but much, much different. Nothing looks the same".