The Battle of the Somme is probably one of my favorite battles in history.
I don't remember the specifics, but on opening day some 20,000 Brits were machinegunned down within a thirty minute timeframe over a two mile stretch of land. By day's end, the estimated casuality count was upwards of 60,000. This specific event led to the 'horror' prescribed to trench warfare in WW1.
Makes me a little sad :'(
What's your favorite historic battle?