In order to clean the water properly, the Maya built a massive filtration system into their reservoir, which at times could hold almost 58 million liters of water. One point that's made that is particularly remarkable to me is that the Maya's discovery and use of this mineral predates the next recorded use of a water filtration aid with this particular mineral by quite a large amount of time. How much time do you ask? Well, the next known use of for water purification wasn't until the 20th century