sentences:  Market Street, which cuts across the city for from the waterfront to the hills of Twin Peaks, was laid out originally in an 1847 survey by Jasper O'Farrell, a 26-year-old trained civil engineer who had immigrated there.Market Street was described at the time as an arrow aimed straight at "Los Pechos de la Chola" (the Breasts of the Maiden), now called Twin Peaks.Property owners forced O'Farrell to retain the earlier Vioget-drawn north-south Yerba Buena street grid rather than conform the roads to the hilly topography; they also forced him to establish the diagonally-offset grid south of Market with larger blocks aligned with Mission Street for Happy Valley.