Sanborn Maps at the WHS. "...Sanborn maps were published between the 1870s and 1950s so local insurance agents could assess the risk of fire breaking out on a client's premises. They outline each building, including the type of heating, size and number of stories, the location of windows and doors, and similar structural features. Through color coding, they even show the composition of building materials. They also document the strength of the local fire department and the presence of hazards such as blacksmith forges, bakeries or stored kerosene, and the existence of firefighting equipment, cisterns or community water works. They also note streets, rivers, canals, railroad corridors and other topographic features. Most Sanborn maps focus on downtowns, but some include large portions of residential areas. Individual homes are recorded with the same precision as large factories."