Bootstrap - Navbar

O que há de errado no botão "Toggle Navigation"?

Ele simplesmente não funciona!

 <nav class="navbar navbar-default navbar-fixed-top">
 <div class="container">
 <div class="navbar-header">
 <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-responsive-collapse">
 <span class="icon-bar"></span>
 <span class="icon-bar"></span>
 <span class="icon-bar"></span>
 </button>
 <a href="index" class="navbar-brand">FancyRealm</a>
 </div>
 <div class="navbar-collapse collapse navbar-responsive-collapse">
 <ul class="nav navbar-nav">
 <li class="active"><a href="index"><i class="glyphicon glyphicon-home"></i> Home</a></li>
 <li><a href="[http://loja.fancyrealm.net](http://loja.fancyrealm.net)"><i class="glyphicon glyphicon-shopping-cart"></i> Loja</a></li>
 </ul>
 <ul class="nav navbar-nav navbar-right">
 <li><a href="login"><i class="glyphicon glyphicon-log-in"></i> Login</a></li>
 <li><a href="register"><i class="glyphicon glyphicon-edit"></i> Cadastre-se</a></li>
 </ul>
 </div>
 </div>
 </nav>