This photo is a view of Jordan Pond, looking across at the South Bubble in Acadia NP. It is thought to be the remnant of a glacier. This water is so clear that you can typically see 44 feet down. I’ve found that it is very hard to judge the depth of the water when it is so clear. Of course, it is also very difficult to judge the depth of the water when it is very murky! I guess you could say the difference is in seeing or not seeing what you don’t know.
It is said that “Seeing is believing” but it is important to remember that we are easily misled by what we see.