Check out a wonderful video about downtown's Mason Theatre (aka Mason Opera House) produced by The 1947 Project.
It's been on the web for several years but I just yesterday came across a link to it. Truly delightful.
The video on Google: "Mason Opera House." Also visit the 1947 Project website if you're an L.A. noir fan.
And for more on this now demolished treasure, see the Mason Theatre page.