Musical Ritual in Mexico CityOn the Zcalo, the main square of Mexico City, Mexico's entire musical history is performed every day. "Mexica" percussionists drum and dance to the music of Aztec rituals on the open plaza. Inside the Metropolitan Cathedral, choristers sing colonial villancicos. Outside the National Palace, the Mexican army marching band plays the "Himno Nacional," a vestige of the nineteenth century. And all around the square, people listen to the contemporary sounds