turning a div into transparent to see through two containers

Question

I have following markup

Answer 1

What you are asking to do will not work using transparency.

However, there is a work around that is quite acceptable:

body {
    background: url(http://placekitten.com/g/400/500);
    background-attachment: fixed;
}
.holder {
    width: 500px;
    height: 700px;
    background: rgba(255,255,255,0.8);
    border: 1px dotted blue;
}
.circle {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: url(http://placekitten.com/g/400/500);
    background-attachment: fixed;
}

see demo at: http://jsfiddle.net/audetwebdesign/FqMXz/

Just apply the same background image to the .circle div.

This trick is taken from one of the CSS books by Eric Meyer.