How to remove white space between nested divs

Question

How can you remove white space between divs nested within each other. For example

  <div>
   <div>
   </div>
   </div>

Answer 1

Could you specify which space are you referring to with reference to the below link http://jsfiddle.net/meghanagpal/4khuL01a/1/

HTML
<div class="default"></div>
<div class="default"></div>
CSS
.default{    
    height:100px;
    width:100px;
    border:1px solid red;
}