title: Responsive embed in Bootstrap 3 doesn't work
body: <p>Hello im creating a web site with Bootstrap 3, everything was going well till i tried to put a Youtube video in my site, so i used responsive embed class that Bootstrap provides but when i display the content of my website the video doesn't show it, i've tried many things like copying the code exactly of Bootstrap page but it still does not work!. Can someone help me?. This is my code:</p>
  
  <pre><code>&lt;!-- PROMOTIONAL VIDEO --&gt;
  &lt;section class="wrap" id="promo-video"&gt;
      &lt;div class="container"&gt;
  
      &lt;div class="header-section"&gt;
          &lt;h2&gt;Mira el video de presentacion&lt;/h2&gt;
      &lt;/div&gt;
          &lt;div class="row"&gt;
              &lt;div class="col-sm-8 col-sm-offset-2"&gt;
                  &lt;!-- 16:9 aspect ratio --&gt;
              &lt;div class="embed-responsive embed-responsive-16by9"&gt;
              &lt;iframe class="embed-responsive-item" src="https://www.youtube.com/watch?v=H0uvGe0AhNI"&gt;&lt;/iframe&gt;
              &lt;/div&gt;
              &lt;/div&gt;&lt;!-- .col --&gt;
          &lt;/div&gt;&lt;!-- row --&gt;
  
      &lt;/div&gt;&lt;!-- .container --&gt;
  &lt;/section&gt;
  &lt;!-- END PROMOTIONAL VIDEO --&gt;
  </code></pre>