The chinampería is an ancient agricultural site in San Gregorio Atlapulco and three other pueblos in Xochimilco. The chinampería consists of plots of land, called chinampas, that were built on a shallow lake. They're formed by making a rectangle (usually 10'x100') using the branches of the huejote tree (a species of willow) and then filling it with mud and vegetation.
The land is still cultivated and produces a large portion of the produce for Mexico City. It's estimated that the chinampería in San Gregorio is between 1,200 and 2,000 years old. Archeologists have found evidence of chinampas dating back between 5,000 and 6,000 years.