Twitter Bootstrap Thumbnails Multiple Rows

HTML

<link rel="stylesheet" href="//netdna.bootstrapcdn.com/twitter-bootstrap/2.2.1/css/bootstrap-combined.min.css">
    <div class="row-fluid">
        <div class="span6">
            <h2 id="clients">Clients</h2>
            
            <!-- First Row of Thumbs -->
            <div class="row-fluid">
                <ul class="thumbnails">
                    <li class="span3">
                        <a href="#" class="thumbnail"><img src="http://placehold.it/220x100" alt=""></a>
                    </li>
                    <li class="span3">
                        <a href="#" class="thumbnail"><img src="http://placehold.it/220x100" alt=""></a>
                    </li>
                </ul>
            </div>

            <!-- Second Row of Thumbs -->
            <div class="row-fluid">
                <ul class="thumbnails">
                    <li class="span6">
                        <a href="#" class="thumbnail"><img src="http://placehold.it/220x100" alt=""></a>
                    </li>
                    <li class="span6">
                        <a href="#" class="thumbnail"><img src="http://placehold.it/220x100" alt=""></a>
                    </li>
                </ul>
            </div>
        </div>

        <div class="span6">
            <h2 id="testiominals">Testemunhos</h2>

            <blockquote>
                <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.</p>
                <small>Someone famous <a href=""><cite title="Source Title">Source Title</cite></a></small>
            </blockquote>

            <blockquote>
                <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.</p>
                <small>Someone famous <a href=""><cite title="Source Title">Source Title</cite></a></small>
            </blockquote>

            <blockquote>
                <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.</p>
        ...