WWI and WWII is something I've found fascinating my whole life. Nowadays with films on demand thanks to YouTube, Netflix, The Smithsonian et al, there's an abundance of stuff to watch. Gone are the days where you'd have to wait all week for the next episode.
Watching the PBS series "American Experience: The Great War" about WWI is probably the best footage I've ever seen on that war. However, it's the horror of how many died and the ways in which they died that is the big takeaway. A million dead at the Somme? That's beyond comprehension. Gas attacks. Machine guns. Trench warfare. Soldiers mowed down as if they were nothing.