The In Focus feature of The Atlantic's blog - which should be a regular stop, it's really well done - is digging into the photographic history of World War I. It's begun a 10-part series covering the war, with a new part posting every Sunday.
This past Sunday was the second installment, which focused on the earlier years of the war on the Western Front. The images drive home the utter destruction of the first truly modern war:
That's what was left of a small town in France that changed hands countless times over four years (via the National Library of Scotland). Go check out the rest and ponder what we, as a species, did to each other for four long years
As a postscript, here's a wonderful IQ song about a soldier who survived the war and returned decades later. Powerful stuff.