We were wandering through a remote bit of Belgian forest the other day, and happened upon this puddle, pictured above.
I know it doesn’t look much like a puddle, because I’m taking the shot from above and you can see the sky and the trees (and me!) reflected on the surface.
But have a closer look, especially towards the top right of the image, and you will see a staggering level of clarity in there. The finest dirt and dust particles have lain undisturbed for god knows how long, and the water itself has become almost invisible.