There is somewhere quite low in the Western USA - Death Valley?
Also I have a slight inkling that there is somewhere called the 'something' Depression.
Death Valley is about 90 metres below sea level, and is one of ten well known depressions in the earth’s surface. Others include the Dead See Depression (420ish) metres, the Afar Depression (150m ish), San Julian’s Great Depression (100m ish).... none of these are the answer I’m looking for
There is the Dead sea depression.
Are we talking about a mine of some description or are we talking about somewhere covered by a glacier rather than an ocean ?
There are mines that are much lower, and given that some of these are still in commercial use it’s hard to be certain which is the lowest. The lowest (from surface) artificially made point with open sky may be the Bingham Canyon open-pit mine, Salt Lake City, United States, where the bottom of the mine is 1,200*m (3,900 feet) below surface level.
However, I’m looking for somewhere which is not man made, and glaciers is a great clue...