Digital Sanborn Maps, 1867-1970 (California) This link opens in a new windowThese maps were originally made to provide information to insurance companies. In a given city, they go block by block, building by building, and show you what was where when. For instance, if you were interested in San Francisco's Chinatown in the 1880's you can see what buildings and businesses were there - you can also use them as primary documents for language use, as you will find what we now consider derogatory language for some buildings and businesses.