I read an article recently about gelatinous fish that live deep underwater, and if they were brought up to the surface would 'melt' due to the lower pressure not supporting their bodies.
This got me thinking, if a human were to go down to the bottom of the Marina trench if it were not underwater (so basically just a 11km deep; below sea level valley), would we be crushed by the pressure of all the extra air above us?
For clarity based on the comments: yes, all the water would be replaced with air. Not just fill with existing air flowing in from around.
Best Answer
This would be equivalent to scuba diving at a depth of roughly 35 meters, or 115 feet. People do it routinely, it causes no health problems, and you don't need to breathe special, low-oxygen-and-nitrogen mixtures as you would in order to go much deeper. However, after spending much time at that pressure, you would need to decompress slowly in order to avoid forming dangerous nitrogen bubbles in your blood ("the bends"). You can check out a dive table to see how gradually you'd need to decompress in order to emerge safely from a given amount of time spent at this pressure.