Apart from their daily or weekly regular markets, most fair-size Mexican towns celebrate one or more yearly markets such as the one above, the "Feria Artesanal del Mundo Maya," which took place in Mérida, the Yucatan, from March 23 to March 27, 2001. A "feria artesanal" usually consists of lined-up booths in which artisans from many places display and sell their products. The above banner says, in translated English, "Direct sales of handicraft from: Chiapas, Tabasco, Campeche, Quintana Roo, Yucatan, Guatemala, Honduras, Belize and El Salvador. Craft fairs are not traditional Mexican mercados. No produce is sold in them, useful items such as machetes and masa grinders are not sold, and such fairs are more patronized by tourists and the curious than by local people needing their daily food and goods.
The same can be said of religious festivals such as the one held each 8th of December in the town of Pátzcuaro, Michoacán. This fiesta honors the Virgin de la Salud, or Virgin of Health, a statue from the 16th century venerated locally for its healing powers. In early May the town of Tepoztlán, Morelia stages a week-long fair during which tourists flock to watch the villagers gamely perform ancient Aztec dances. On each January 23rd, St. Ildefonso Day is richly celebrated in San Ildefonso, Querétaro. On each last Sunday in September, Atlixco, Puebla celebrates St. Michael the Archangel Day by staging Indian dances and a huge tianguis. These festivals may indeed have roots in antiquity and hold very important places in the lives of local people, but they are religious in nature, not commercial, so they are not traditional Mexican mercados.
Some once-a-year Mexican mercados feel like state fairs in the U.S., especially in Baja California and most of northern Mexico. Each year, for instance, the cities of Monterrey, Nuevo León, and Ciudad Juárez stage important commercial and agricultural fairs.
But, in mentioning these high-powered, Chamber-of-Commerceish events, we're drifting far from the kind of down-home Mexican mercado this site is about.