How far below sea level could humans survive?

Factual Questions
1

The Dead Sea is an interesting place. Since it is below sea level, atmospheric pressure there is a little bit higher. That means there is more oxygen.

Let’s pretend we have an incredibly deep valley- say, 6,000 meters below sea level. Could humans survive, or would the air pressure become too high? What would the weather be like?

2

You would probably need waders with all the magma and stuff.

3

Must… resist… joke… about when and for what amount of time man has visited the deepest part of the ocean…

Phew.

I’m sorry. Carry on.