Known as El Pueblo de Los Angeles Historical Monument, and not the original center of Los Angeles, the Plaza and adjoining Church were relocated westwardly to the present site after the great flood of 1815 when the river jumped its banks moving towards the west and overflowing the church's foundations.
The Plaza formed the heart of the new city with a surrounding rectangular border, from which streets were planned and formed outwardly. The lots surrounding the Plaza were granted to the wealthy early residents. A house with its front to the Plaza was a prestigeous property. Lots were assigned in general terms with the understanding that the Plaza area remain rectangular, but lax building rules and plot extentions eventually forced the city to make the area circular, as it is now. At its perimeter is Our Lady Queen of the Angels church to the west, Pico House to the south and Olvera Street to the north.
http://www.elpueblo.lacity.org/index.htm125 Paseo de la Plaza, Los Angeles, CA 90012