Note: There is a chance that there may be no Grito in the Zócalo in 2013 as teachers are currently occupying the square in protest of educational reform. Even so, there are plenty of other places in Mexico City to celebrate (such as in the Coyoacán neighborhood), and, indeed across the world.
If you find yourself in Mexico City in the second week of September, you'll see the city at its most festive and patriotic. National flags hang from buildings; novelty costumes, hats and Pancho Villa-esque moustaches are on sale on almost every street corner, and bakery windows are stacked high with colorful patriotic cakes.
The reason for this display of national pride is that September 16th is Mexican Independence Day, which marks the beginning of the Mexican War of Independence. The day is celebrated with parades and festivals, and with food prepared in the color of the Mexican flag, such as chiles en nogada made up of green chili pepper, white walnut sauce, and red pomegranate seeds.
It is the night before, however, that you'll experience the most inspiring tradition of the Fiestas Patrias (patriotic holidays): El Grito.
Why Go: Late in the evening of the 15th, thousands of people dressed in traditional costumes and with faces painted in patriotic colors stream into the Zócalo (the main square; one of the biggest in the world) for a festival that includes performances by both traditional and contemporary artists, and culminates with the President of Mexico marching to the Palacio Nacional balcony to repeat the "Grito de Dolores." The Grito was a call to arms made by Miguel Hidalgo in 1810 that began the struggle for independence from Spain, which was finally achieved in 1821.
The grito starts with the President ringing a bell and then shouting out the names of Mexico's heroes. As each name is read, the crowd, in a call and response style, cry out ¡Viva!
The Grito ends with the president ringing the bell again and waving the Mexican flag as fireworks shoot into the sky, and the crowd cheer and sing the Himno Nacional Mexicano to the accompaniment of the Mexican Armed Forces band.
What to Know: Mexico got a new president (Enrique Peña Nieto) last year and so it remains to be seen how his Grito stacks up to that of his predecessor, Felipe Calderón (which gave me goosebumps when I heard it last year). What we do know is that for the six years of his presidency, he will repeat the following words from the main balcony of the Palacio Nacional at 11pm on September 15th:
¡Vivan los héroes que nos dieron patria! (Long live the heroes who gave us the homeland)
¡Viva Josefa Ortiz de Domínguez!
¡Vivan Aldama y Matamoros!
¡Viva la independencia nacional!