César Estrada Chávez (March 31 1927 – April 23 1993) was a Mexican American farm worker, labor leader, and civil rights activist who with Dolores Huerta co-founded the National Farm Workers Association, which later became the United Farm Workers. blank">http://www.extramile.us/honorees/chavez.cfm Supporters say his work led to numerous improvements for union laborers. He is considered a hero for farm laborers, and opposed both legal and illegal immigration to help keep wages higher and improve work safety rules. He is hailed as one of the greatest American civil rights leaders. His birthday has become _a holiday in four U.S. states. Many parks, cultural centers, libraries, schools, and streets have been named in his honor in cities across the United States.