Bunker Hill, Hope Street looking south from 3rd, 1956
Bunker Hill, Hope Street looking south from 3rd, 1987
Notice the pyramid roof of the Central Library; it's very obvious in these shots that Bunker Hill was regraded and made lower.
I read somewhere that one plan for Bunker Hill redevelopment was to remove the hill entirely, and of course other hills in downtown LA were removed, but for some reason they went with just flattening Bunker Hill somewhat.
Here's another evolution of a downtown section:
Looking southwest from Hope and 4th, 1968
Same scene, 1969
Same scene, 1970
Same scene, 1971
Same scene, 1990
All pics from lapl.org