65,035 feet
The Mariana Trench is the deepest point on the Earth's surface.
If you scan the literature, you will find various numbers for the depth of the Mariana Trench. It boils down to:
about 36,000 feet below sea {level;}
which is about 6.8 miles {down;}
and that equals about 11,000 {meters;}
or 11 km.
That makes the Mariana Trench quite a few feet deeper than Mount Everest is high. If you scan the literature, you will also find several numbers for how high Mount Everest is. NASA currently gives it as 29,035 ft. or 8850 meters.
Therefore:
36,000 + 29,035 = 65,035 feet
Your choice af asking 'approximately'' is supported by the following site the source of the above {information;}
http://geology.com/records/deepest-part-of-the-ocean.shtml
