Yes, that one!
The movie was bad, also the title is funny. But I remembered the WWI part because it's unlikely to see such in movies nowadays.
yeah more like a docufiction then a movie, but interesting if you are into those kind of tv shows. Also who played einstein was a pretty cool actor
A really good docufiction with awesome and historically accurate battles is also Hannibal: Rome's worst nightmare.
The cannae battle in that movie is one of the most accurate and brutal depiction of an ancient battle ever.
Also i liked that for once the romans aren't depicted with that lame lorica segmentata and late helmet and late army organization, but have the real early republican stuff (bronze little breastplate or no armour at all, and montefortino helmet) and quite bad tactics relying only on sheer numbers and choesion.
Also there is Ancient Rome The Rise and Fall of An Empire that have good battle historical accuracy but with good actors and some action. Don't watch the usa version, it's just a documentary with standard lorica segmentata battle scenes on the background for every battle.
Watch the uk (bbc) version it's more like a movie and also much more accurate