Cesar Chavez!

Cesar Chavez (1927 - 1993) was an mexican american farm worker and civil rights activist so important for America because he with Dolores Huerta cofounded the National Farm Workers Association which later became United Farm Workers (UFW). Basically UFW is a labor union created by the union of two groups and one of this group was led by Cesar. This guy was so important because this union changed some civil rights to have to worker's credit, like unemployed insurance when the NFWA went out on strike when had initiated a grape strike in 1965. So, the UFW launched a boycott against of grapes and after five years they won a contract with the major grape growers in California.
In honor of him, today there is a street in SF and other things like many parks, cultural centers, libraries and things like this which his name. After his death he became a major historical icon of the Latino community and it means like a support for workers and their rights.
Cesar Chavez Day is a state holiday in three states of the United States (California, Colorado and Texas) and it is on March 31, in honor of his birthday.