For many foreigners, Xochimilco conjures images of an afternoon of beers and mariachi bands while soaking up the sun on one of the colorful boats known as trajineras that navigate the waterways here. But there's so much more to Xochimilco than booze and boats. There are the collectives that practice small-scale agriculture on the man-made islets called chinampas, the vendors that sell food that is as close to its pre-Hispanic roots as you can get and, of course, the market. More