On the way back from Traverse City, since we had some extra time, we decided to stop at some random state park. Luckily, we decided to stop at this Higgins lake which looked quite ordinary on the map.
But when we reached there, we were confronted with this beautiful lake with the clearest water I had ever seen. Well you can't really make that out in the photo below (and it's not a particularly flattering pic of any of the three of us), but what you will notice is that the is a region closer to the photographer is light green/blue in color and it transitions abruptly to a deep blue color.

We swam almost to the edge of the transition and used our swimming goggles to check out what the color change was all about. And the sight was a real scary one. We could clearly see the lake bed for about 8-10 feet in front of us and then it seemed as if there was nothing at all beyond that. After some deliberation, I decided to swim right to that edge, and when I just about reached the edge, I saw the lake floor slant down at more than a 45 degree angle and disappear into the depths of the clear blue water. Of course, I immediately turned back and swam as fast as I could to safety.
Although I think I won't be scared to swim in the middle of the lake, seeing the lake floor disappear into the distance was very scary. It was almost like vertigo.
A similar comparison:
You won't be scared to view Chicago from the top of the 100+ storied Sears towers (from a safe glass covered indoor viewing area), but one would be much more scared to stand at the edge of a windy 10th floor balcony with no guard rails.
The image of the disappearing lake floor still haunts me. :)
p.s. Lake Higgins is voted the 6th most beautiful lake in the world by National Geographic.