Paths of Glory is really good.
All of Kubrick's films, without fail, are.
Basically, its my understanding that the British and the Germans were heading towards war because of their rivalry over trade and colonial expansion, basically there were two groups of oligarchs with similar colonial ambitions locked into a bitter rivalry with one another, with a Franco-German economic struggle over iron and coal also being important.
Imperial Russia also wanted to control the straits between the Black Sea and the Mediterranean while Germany saw Russia as standing in the way of its eastward ambitions, which included a proposed Berlin to Baghdad railway that was supposed to also cement a relationship between Germany and Turkey..
Britain saw this as threatening their position in India and Russia as threatening their position in Persia.