> I wonder if militaries have more mapped but consider it secret. Almost certainly, although I expect they focus a lot more on some areas than others. And the

> I wonder if militaries have more mapped but consider it secret. Almost certainly, although I expect they focus a lot more on some areas than others. And they probably care about the deepest parts of the ocean floor less than the rest; if the ocean is so deep that it crushes anything short of a bathysphere, then it's probably less important to have precise maps of the ocean floor in those areas.