Unable to render menu in theme I'm creating a custom theme in Drupal 7 but I'm having trouble getting it to render the menu

I'm using the following code in page-front.tpl.php

&lt;?php if ($page['main_menu']): ?&gt;
    &lt;div id="main-menu"&gt;&lt;div class="section clearfix"&gt;
&lt;?php print render($page['main_menu']); ?&gt;
    &lt;/div&gt;&lt;/div&gt;


But it does not render anything. I have double checked that a menu exists.
$page['main_menu'] is not menu. It's the region with name main_menu. You can put there any block what you want. You can configure blocks on this page admin/structure/block

But in the basic drupal themes the main menu can be available in this variable $main_menu in the template page.tpl.php