1885 1896 1915 1930 1938 1940 1956 2007 1890s 6th street bridge 7th street bridge aqueducts bridges construction development displacement dogtown downey avenue downey avenue bridge elysian hills elysian park engineering fences floods future green griffith park hills infrastructure islands labor land use lashp los angeles river macy street bridge maps nature north broadway bridge parks people plans public space railroad tracks railroads recreation renderings skylines streets trees walkability water william mead homes zanjas