I am trying to implement a modal using bootstrap. When I click on the button the screen fades and the modal appears, but it appears behind the images in and is unreadable for the user. How do I bring the modal forward?

<div class ="container-fluid">
<div class = "row-fluid">

    <div class = "span2">
        <!-- Modal -->
        <div class="modal hide fade" id="myModal">
          <div class="modal-header">
            <a class="close" data-dismiss="modal">×</a>
            <h3>Modal header</h3>
          </div>
          <div class="modal-body">
            <p>One fine body…</p>
          </div>
          <div class="modal-footer">
            <a href="#" class="btn">Close</a>
            <a href="#" class="btn btn-primary">Save changes</a>
          </div>
        </div>

        <a data-toggle="modal" href="#myModal" class="btn btn-primary">Launch demo modal</a>
    </div>

    <div class = "span8">       
        #a lot of images in this div
    </div>

</div>
</div>