googletag.defineSlot("/1234/travel", [[300,250],[300x600]], "div-gpt-ad-123456789-0"))


 <div id="div-gpt-ad-123456789-0" style="width: 728px; height: 90px">
  <script type="text/javascript">
      googletag.cmd.push(function() {
      googletag.display("div-gpt-ad-123456789-0");
      });
    </script>
  </div>