In Bonaire, the sea is very transparent. When swimming out into the sea, there is a point where all of a sudden the bottom of the sea deepens so abruptly, it goes from seeing the seabed clearly, to a huge black hole, without any transition, it completely disappears from view. Reaching this point left me feeling really scared. Even though it has no physical consequences for my swimming on the surface. Still, I almost did not dare to swim past this point. I felt like standing on the edge of a cliff.