Jalisco is the birthplace and primary production zone of tequila, accounting for the vast majority of the spirit's output. The state contains two principal growing zones: the highlands (Los Altos), where red clay soils and cooler temperatures produce larger agave plants yielding sweeter, fruitier tequilas; and the lowlands (Tequila Valley), where volcanic soil and warmer conditions create earthier, more herbaceous expressions. Only Blue Weber agave (Agave tequilana) may be used. Major producers based in Jalisco include Jose Cuervo, Sauza, Patrón, Don Julio, Herradura, and Fortaleza. The town of Tequila is a UNESCO World Heritage Site.