I saw that show too. If you really want a great source on WWI listen to Dan Carlins Blueprint for Armegeddon. Absolutely amazing, I learned so very much from that podcast and the details will amaze you.
I will try to quote one from memory. He speaks about Russia and how at the start of the war they are producing 35k artillery shells a month. Sounds pretty good right? Until you find that ince the war starts they are firing 45k shells a DAY!
The statistic that always boggles my mind is that at Verdun, the French and the Germans fired something like the equivalent of 10 tons of TNT for EVERY SQUARE YARD of the battlefield.