Bugün öğrendim ki: Dünyanın en berrak gölü Nelson, Yeni Zelanda'da bulunan Mavi Göl'dür. Gölde görüş mesafesi 80 metreye kadardır, yani su optik olarak neredeyse damıtılmış su kadar berrak kabul edilir.
Scientific tests carried out in 2011 by New Zealand's National Institute of Water and Atmospheric Research (NIWA) showed Blue Lake to be the clearest natural body of fresh water known to man. According to the NIWA research results, visibility in the lake is up to 80 meters - meaning the water is considered almost as "optically clear" as distilled water. Blue lake is characterized by blue-violet hues seen only in such clear natural waters. Part of the Nelson Lakes National Park conservation area in the northern South Island, Blue Lake is fed by waters from nearby Lake Constance. The park is a popular hiking, fishing and destination. The lake is a two-day hike from the park boundary or, for an aerial view, there are scenic flights with Reid Helicopters.