http://www.edwardtufte.com/tufte/posters

From the page:
“Probably the best statistical graphic ever drawn, this map by Charles Joseph Minard portrays the losses suffered by Napoleon’s army in the Russian campaign of 1812.

Beginning at the Polish-Russian border, the thick band shows the size of the army at each position. The path of Napoleon’s retreat from Moscow in the bitterly cold winter is depicted by the dark lower band, which is tied to temperature and time scales.”

Update: 2022 – this site has stayed online and intact – which is great. For more info on Tufte check out his wikipedia page. This is just one of the many interesting links I recorded via stumbleupon.