Military body armor has improved drastically over the last few centuries, and we have the details how.

For this video, we actually unearthed through an old 1920 report from the Library of Congress which had a ton of first-hand information on how effective body armor has been throughout the ages.

Then we looked at new data and found out twice as many soldiers in Iraq were taken out of action from back injuries than from combat. Yikes.

Check out the video above for more details.