$template_dir
     This is the name of the default template directory. If you do
     not supply a resource type when including files, they will be
     found here. By default this is
     "./templates",
     meaning that Smarty
     will look for the
     templates directory in
     the same directory as the executing php script.
    
Technical Note: 
      It is not recommended to put this directory under
      the web server document root.