Memória de Rio

São Paulo, Brazil, is the most populous city in the Southern Hemisphere, and its region, home to twenty million people, is the third-largest metropolitan area in the world. The Tietê River, which flows through it, has been a precious source of drinking water for centuries, but today, as Roney Freitas tells us in a veritable river elegy, it is highly polluted due to untreated sewage and industrial waste that has been pouring into it for years.