Why I think this is important
If you like maps, you have to check out the Stanford Library’s site “Data Visualization and the Modern Imagination.” There are maps pertaining to all kinds of subjects like “Animal and Vegetable life of the Different Zones, “A Map of Vesuvius,” and “The Daily Number of Trains” in France in 1896.
For US History fans, there are maps on the Ethnography of North America, population of the US Census in 1870 and 1880, and this W.E.B. DuBois map of the Seventh Ward of Philadelphia from his book “The Philadelphia Negro.”
What a wonderful resource for the visual representations of heavily detailed data!