Draw Circle using css alone [duplicate]

Yep, draw a box and give it a border radius that is half the width of the box:

#circle {
    background: #f00;
    width: 200px;
    height: 200px;
    border-radius: 50%;
}

Working demo:

http://jsfiddle.net/DsW9h/1/

#circle {
    background: #f00;
    width: 200px;
    height: 200px;
    border-radius: 50%;
}

<div id="circle"></div>