Wow, I was just in France last month and visited the Douaumont ossuary near Verdun. The whole area is eerie. The landscape is just as shown in those photos. It looks like a moonscape. Just driving along, you see craters and hills on both sides of the road. Metal still sticking out randomly. Decaying bunkers all around.
The ossuary itself was an incredible place (120,000 buried there). For those of us not from Europe, it was a lesson in the horrors of WWI that was present for the residents of the continent that has no equal in the US.
I think you might underestimate how bloody the American Civil War was, especially since it was 50 years before the improved killing technologies of WW1.
There were more casualties in just this one battle than in the whole Civil War though. And the Battle of the Somme that was being fought at the same time had even more dead in the same timeframe.
These two battles fought in 1916 add up to more dead soldiers than there were participants in the whole Civil War. The combined population of France and Germany in 1916 was also about three times that of the US in 1860, but I think that doesn't make up for the x10 casualties.
That's total killed for all combatants during WW1 though. American casualties during the Civil War were comparable to European countries individually during WW1.
The ossuary itself was an incredible place (120,000 buried there). For those of us not from Europe, it was a lesson in the horrors of WWI that was present for the residents of the continent that has no equal in the US.
https://en.wikipedia.org/wiki/Douaumont_Ossuary