Feeling nostalgic? There’s a great collection of historic photographs of Los Angeles (1920-1990) available at http://unitproj.library.ucla.edu/dlib/lat/ .
You can browse by subject (from Aaron Brothers to Zuma Canyon) or you can search by keyword. I browsed for Hollywood and got 37 results, which included thumbnails and covered subject as diverse as an Easter service at the Hollywood Bowl (1947) to Donald Duck getting his footprints at Mann’s Chinese Theater (1984) to Lawrence Welk signing autographs during his appearance at the Hollywood Palladium (1961).
Each search result has a larger version of the picture along with published caption, publication date and periodical where it was published. Visitors might also be interested to know that all the photographs I looked at were Creative Commons licensed as Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.