Lake Tovel in Italy used to turn red in the summer. Here is both the reason why from both a legend and a scientific viewpoint: http://www.albergolagorosso.it/en

Lake Tovel in Italy used to turn red in the summer. Here is both the reason why from both a legend and a scientific viewpoint: http://www.albergolagorosso.it/eng/perche_lago_rosso.php http://www.albergolagorosso.it/eng/perche_lago_rosso.php