Japan/Hokkaido: Biei – Blue Pond
In 1988 Mount Tokachi volcano erupted in central Hokkaido, threatening the small town of Biei with mudflows. An artificial pond was dug out to protect the town and over time it filled with water. The runoff and ground water were very high in aluminum hydroxide which gave the water blue color, sharp and deep blue color. The lake is somewhat similar to the one in Iceland that was also artificially made and is also this sky-blue color.