Hi, I'm learning BS and I think I get this grid system thing. I was wondering If someone could check my code and let me know if there was a better way to do it?

The jsFiddle comes out a bit weird, but on a normal browser it looks right though: http://jsfiddle.net/n2fole00/ABqUV/3/
HTML Code:
<div id=class="container">
<div class="row"><!-- MAIN ROW -->
        
    <div class="col-sm-5 col-box">
        <div class="row">
            <div class="col-sm-12 col-box">
                <h3>CONTENT ONE</h3>
            </div>
            <div class="col-sm-12 col-box">
                <h3>CONTENT TWO</h3>
                <h3>CONTENT TWO</h3>
                <h3>CONTENT TWO</h3>
            </div>
        </div>
    </div>
       
    <div class="col-sm-7 col-box">
        <h3>CONTENT THREE</h3>
        <h3>CONTENT THREE</h3>
        <h3>CONTENT THREE</h3>
        <h3>CONTENT THREE</h3>
    </div>
        
    <div class="col-sm-12 col-box">
        <h3>CONTENT FOUR</h3>
    </div>

</div><!--/END MAIN ROW -->
</div><!--/END CONTAINER -->
Thanks