We all know I'm a map guy, but old photos are nifty too.. and there are a whole bunch of them over on the Smithsonian flickr photostream
. A fine example? Marie Curie, the famous chemist:
It's interesting to note here that Marie was working with radioactive materials in her research by the turn of the century and was hospitalized with kidney problems in 1911. This photo is over two decades later, taken in the same year as her death, and you can tell she isn't in tip-top shape.
My sister currently works in Paris at the Institut Curie and the building, still to this day, has raised levels of radioactivity.