In the south of Mexico City, about 100 miles of murky canals wind their way through the Xochimilco neighborhood. Here, the urban sprawl of one of the world’s densest cities yields to a lake region where indigenous farmers have been cultivating a unique system of floating gardens since pre-colonial times. Called chinampas, these floating gardens were built by the Aztecs to feed a growing population. Xochimilco became one of the city’s main sources of food, but rapid urbanization in the 1900s meant less land available for farming. In 1985, when…
