... that I find particularly good.

high-res color original French
lower-res b&w English translation

The chart shows:
* horizontal & vertical: geographic location of the army within Russia
* thickness & numbering: population of the army (from 422k -> 100k -> 10k)
* to and from (light / brown = entering, black = returning)
* temperature & dates on return trip
* movement of reserves
* major rivers

... and all quite comprehensibly.