drink mezcal or beer-based punch called "heribertas" for free. According to tradition, these parties were begun by a college student named Heriberto, whose last name has been lost. They are most commonly held at the end of the school year, but no reason is needed to hold one. Most callejoneadas form in front of the Palacio de Gobierno, where a "tambora" band or other type of band, a group of revelers and a donkey carrying jugs of "heribertas" gather. The donkey is often painted or otherwise decorated. The party then winds its way around the narrow streets and alleys of the city, with people drinking the heribertos from little jars called jarritos. Most of the revelers are students but all are welcome to join. Zacatecas is the seat of a United Nations Educational, Scientific and Cultural Organization (UNESCO) Category II Regional Office, to promote training, research and conservation of artistic, historical, natural and archaeological heritage of Mexico, Central America and the Caribbean. It is the fourth such office to be established after those in China, Brazil and Bahrain. The office is in charge of fourteen percent of the World Heritage Sites in the world. The city's chamber music festival has been held annually since 1993. It is organized by the Instituto Zacatecano de Cultura with support from the Escuela de Musica of the Universidad de Zacatecas as well as other local and national entities. Transportation By highway, Zacatecas is connected to Aguascalientes via Fed 45, to San Luis Potosí via Fed 49, Fed 23 to Guadalajara and Torreón and Fed 54 to Guadalajara and Saltillo. There is a rail line called the "Ferrocarril Central" that still connects the city with other parts such as Ciudad Juárez and Mexico City. The city is served by the General Leobardo C. Ruiz International Airport, which connects the city with Tijuana, Morelia, Leon, and Mexico City. Intercity busses connect the city with other regional cities such as Fresnillo as well as national destinations such as Guadalajara, Ciudad Juárez and Mexico City. There is also transportation to locations such as Plateros, and the Sanctuary of the Niño de Atocha. There is also public transportation intra-city as well. The municipality Geography As municipal seat, the city of Zacatecas is the governmental authority for 180 other named localities, which total an area of . Ninety-three percent of the municipality's population of 132,035 lives in the city proper.