An arch - part of the Fourth Street Viaduct over the Los Angeles River - under construction in 1930.
Part of the California Historical Society Collection in the USC Digital Library.

An arch - part of the Fourth Street Viaduct over the Los Angeles River - under construction in 1930.

Part of the California Historical Society Collection in the USC Digital Library.

The Santa Monica (I-10) Freeway under construction near downtown Los Angeles in 1961.
Learn more about the freeway’s construction in L.A. as Subject’s guest post for KCET Departures, “Creating the Santa Monica Freeway, Building Walls Across Communities.”

The Santa Monica (I-10) Freeway under construction near downtown Los Angeles in 1961.

Learn more about the freeway’s construction in L.A. as Subject’s guest post for KCET Departures, “Creating the Santa Monica Freeway, Building Walls Across Communities.

Construction of the San Diego (405) Freeway, pictured here in 1957 between Wilshire and Venice boulevards, split Westside neighborhoods.

Construction of the San Diego (405) Freeway, pictured here in 1957 between Wilshire and Venice boulevards, split Westside neighborhoods.

LAX’s Theme Building under construction on this day in 1960. Airport Commission president Don Belding waves a flag in the foreground.

LAX’s Theme Building under construction on this day in 1960. Airport Commission president Don Belding waves a flag in the foreground.

Construction of the 101 freeway at Broadway in 1950. On the left is the new broadway bridge; on the right a temporary detour. The hill on the top-left is Fort Moore Hill, one of the lost hills of downtown Los Angeles.

Construction of the 101 freeway at Broadway in 1950. On the left is the new broadway bridge; on the right a temporary detour. The hill on the top-left is Fort Moore Hill, one of the lost hills of downtown Los Angeles.