Might be old hat for most of us here, but still interesting nonetheless:

http://www.kcet.org/updaily/socal_focus/history/la-as-subject/las-changing-skyline-a-brief-history-of-skyscrapers-in-the-city-of-angels.html

^Very informative, thank you for sharing... found this other link in the same site "laws that shaped LA".
http://www.kcet.org/socal/departures/landofsunshine/laws-that-shaped-la/laws-that-shaped-la-why-is-the-la-skyline-so-bland.html