Since the founding of California's El Pueblo de San José de Guadalupe in 1777, people of Mexican ancestry have contributed to make San José a rich cultural, political, and economic epicenter. Mexican miners who worked in the local mines helped San José become one of the top mercury producers in the world. In the 20th century, Mexicans labored in the "Valley of Heart's Delight," as the Santa Clara Valley region was called, picking, canning, drying, and packaging fruits and vegetables for America's dinner table. They paid homage to their cultural heritage as they formed ballet folklórico groups, established mariachi bands, painted murals, and wrote literature. Through grassroots organizing and collective action, countless heroines and heroes, such as labor leader Cesar Chavez, dedicated their lives to improving conditions in their neighborhoods and communities. In 1999, the City of San José acknowledged the contributions of Mexicans with the grand opening of the Mexican Heritage Plaza, a cultural center for the performing arts.