Mariachi both countries, however, the learning of traditional pieces and repertory is still stressed to form a base. The International Mariachi Festival in Guadalajara is an annual ten-day event that attracts more than 500 mariachis, who perform in concert halls and city streets. Past players include Mariachi Vargas de Tecalitlán, Mariachi los Camperos (led by Nati Cano) and Mariachi América. In Mexico City, the center of mariachi music remains Garibaldi Plaza. The plaza fills with mariachi musicians to solicit gigs from individual songs for passers-by to being hired for events such as weddings and baptisms. They even stand on Eje Central
Mariachi problems recruiting mariachi instructors as many of these do not have required teaching credentials. For this reason, schools often hire trained musicians from outside the mariachi tradition. Many traditional mariachis are concerned that standardization will lead to fossilization and restrict improvisation. Other innovations in the United States have been the incorporation of styles of artists such as Elvis Presley, Freddy Fender and Glenn Miller, as well as the heavy-metal Mariachi band Metalachi. Another is the encouragement of female mariachis including all-female Mariachi groups such as Mariachi Mujer 2000 and Mariachi Divas de Cindy Shea. Mariachi Mujer has performed with Mexican