... as reported by Secchi Records:

Wikipedia confirms (or at least repeats) the recording:

The Weddell Sea has been deemed by scientists to have the clearest water of any sea. Dutch researchers from the German Alfred Wegener Institute, on finding a Secchi disc visible at a depth of 262 feet on October 13, 1986, ascertained that the clarity corresponded to that of distilled water.

In case you are interested in the opposite record for turbidity, Secchi Records has




Disk disappearing under an algal scum in Crystal Lake, Ohio


New Zealand is a spectacular country. The photos of Tikitapu are beautiful. Thanks, n2doc.

I can fully understand why and agree with the law, but it's still a bit of a shame. That would be an amazing place to go visit.

And because the original article doesn't make it clear WHY this is so clear: A glacial stream feeds into a moraine lake just above the treeline. That lake has no outlet stream, but instead filters out through the fine gravels in the moraine, which acts like a filter. The filtered water feeds into a second lake immediately below the moraine, right at the treeline. The water flow is high enough so that the entire body of water is replaced each day, removing any minor silting that might have occurred from the surrounding grasses and trees.

It's natures perfect water filter. Please keep Nestle away from it.