Calisphere is a project of the California Digital Library. It's mission is to provide public online access to some of the collections from the University of California Libraries, Museums and contributing public library systems.
The California Cultures website is especially interesting. This gives a visitor the ability to find out information about African American, Asian, Hispanic and Native American cultures.
I decided to explore the Asian American section. There are a number of pathways I could follow such as the Gold Rush Era with an historical overview of the time.
I also was able to view photographs, advertisements and some of the anti-immigration publications of the time. Depending on the amount of documentation available you can find out the source of the photo, the context and related keyword searches to help you access even more information.
Where available there are letters, political cartoons, oral histories and diaries and other materials to aid in researching a topic such as the Transcontinental Railroad.
You could spend hours reading and catching up with the good and the bad of California's history. And you will learn a lot about how different ethnic groups shaped that history.