University of Illinois anthropology professor Lisa Lucero argues in a paper published in the Proceedings of the National Academy of Sciences that ancient Maya reservoirs, which used aquatic plants to filter and clean the water, “can serve as archetypes for natural, sustainable water systems to address future water needs.” The Maya built and maintained reservoirs that were in use for more than 1,000 years, providing potable water for thousands to tens of thousands of people in cities during the annual, five-month dry season and in periods of prolonged drought.