Department of Why War Is Awful
Provided you have the stomach for it, read this article and then watch the clips (one and two) of U.S. soldiers shooting what appear to be unarmed and injured Iraqis, a violation of international law. (In all fairness, the first clip shows an Iraqi who has a gun lying next to him but no longer in his hands. The transcript says he is writhing on the ground next to his gun; the voiceover on the video itself does not mention his gun.)
The first clip, from CNN, after the shooting shows a young soldier saying that the feeling after battle, after killing someone, is "awesome." The second clip — footage from an Apache helicopter, shot at night, and broadcast by ABC News — was in my opinion more harrowing, mainly because it lasts as long as it does.
If you check the links at the bottom of the article above, you will find reactions to the first video by present and former members of the U.S. military, debating the legality and propriety of the shooting, as well as a written piece from ABC News to accompany the video (at least I assume that's what it is; I can't get the page to load).