Deep in the tropical forests of Northern Guatemala, lies the Maya city of Tikal, one of the larger Maya cities, with, at its prime, hosted more than 45,000 people. What kept the city flourishing was its innovative water filtration system, the earliest known of its kind.
A few years ago, researchers excavated sediments from several of Tikal’s reservoirs. They were surprised to find that one of the largest reservoirs, Corriental, had significantly less contamination from unsafe pollutants. This finding suggests the presence of a deliberate filter system crafted by the Maya.
The first hint of an ancient filter was the discovery of quartz crystals. The scientists found four distinct layers, each a few centimeters thick, of brownish, millimeter-scale crystals. Then, the researchers examined the quartz in greater detail and discovered it was dotted with even smaller crystals of “zeolites.” This type of volcanic mineral, that purifies just about everything we drink, from bottled water to wine, traps both microbes and heavy metals within a porous structure.
