 In 1967 it was discovered that the blue green algae natural to Lake Texcoco's alkaline waters (which had previously been filtered and discarded) could instead be deliberately cultivated in the El Caracol basin, collected with screens and processed into dry nutritional supplement powder for commercial sale.Proudly branded as ""Spirulina Mexicana"", the idea resurrected the ancient agricultural practices of the Aztecs, who had collected and traded the edible algae from Lake Texcoco since pre-Columbian times.In 1973 the world's first commercial spirulina plant was opened at El Caracol with a production capacity of 1 ton per day, eventually expanding to a series of plants producing 200 tons a day.