When I was a child, all of the kids in grammar school wore backpacks that contained essentially, our school books, along with magic markers crayons and a smock or two.  It was always fun to see if you could pick someone’s backpack without them feeling the intrusion.  The act was mean-spirited but it was something that kids did.  I was certainly guilty of this and became fairly proficient at this practice.  As you grew older, the backpack was used as an athletic bag, that was either given to you by whatever team for which you competed or purchased at a small cost.  In my case, I ran cross-country and track and needed it to carry my books as well as two pairs of running shoes.  They were a source of pride as they had the name of your school along with your team sport; the winged foot. In college, students carried either backpacks or some type of athletic bag.  I ran in college, so again I purchased a team bag to carry my books and two pairs of running shoes.  When I finally left graduate school and joined the workforce full-time, I bought a briefcase.  It fit nicely on my shoulder and was large enough to carry any necessary paperwork but not so big that it was bulky.  As an adult, the backpack was a thing of the past, or so I thought.  Today, as might be expected, children still wear backpacks.  But so do adults, in record numbers.  Men and women in business suits wearing huge packs on their backs as if they’re hiking to work.  Are they afraid they might run out of food, water and clean clothes between their train stop or garage and their offices?  Are they packing supplies in case of the Apocalypse?  All joking aside, backpacks are everywhere.  Most people own at least one and they have become a source of prestige in schools across this country.  An entire market has been created by convincing people they need to carry lots of crap wherever they go.  It’s the reason people’s guards were down, despite the fact these two brothers just dropped off the bomb laden backpacks and left the scene.  Who would have imagined that something so seemingly innocent as a backpack could be used in one of the most heinous crimes in US history?  But just like people getting involved to stop attacks on planes following 9-11, no one will ever again look away when witnessing a backpack being left on the street or in the subway.  Our world is once again changed forever.