Scientists have identified the largest ancient Mayan dam, constructed from stone and holding back around 20 million gallons of water in a man-made reservoir. The Tikal dam stretched more than 260 feet in length and was 33 feet high, and sheds new light on how the Maya conserved their natural resources for over 1,500 years.

To cope with seasonal and extended droughts, the Maya carefully integrated the built environment – expansive plazas, roadways, buildings and canals – into a water-collection and management system. At Tikal, they collected every drop of water that fell onto these paved or plastered surfaces and sluiced it into man-made reservoirs. The gravity dam is the largest hydraulic architectural feature known in the Maya area, second in size only to the huge Purron Dam built in Mexico’s Tehuacan Valley sometime between AD 250-400.