This former rock quarry is known to locals as the Blue Lagoon. The water is crystal clear and from a distance, strikingly blue. But don’t let its looks fool you. Because of the contents of the lake, the water in the Blue Lagoon is actually not pleasant at all. In fact, it’s as toxic as bleach… but it’s still one of the most popular tourist destinations of the area.
The quarry’s pH is pH 11.3, just less than ammonia at 11.5pH and bleach at 12.6pH.