This line of latitude separates communist north korea and the u. S.- backed republic of korea.

38th parallel line.

Explanation:

It's the 38th parallel line of latitude that separates communist north Korea and the U.S backed republic of Korea. This line is situated at the 38 degrees towards north from the earth equatorial line and is the example of geometric boundary in which borders are closed and a very small movement is allowed across it. Prior to the korean war, this line serves as a border between the north Korea and the south Korea.

sitting in that one chair where he could get shot at was his worst decision.