system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How high and how low do a nations borders go?

Does a bit of earth still count as part of a nation even if it were far below the surface? On the same note does a nations air space go as high as the atmosphere goes or is there a different cut off point?
gpt
National borders are usually understood to travel all the way to the center of the Earth below. Above they extend to the border of the atmosphere with space which is typically defined as 100km in elevation.