https://api.drupal.org/api/drupal/includes%21menu.inc/function/menu_tree...

<h3>
<?php
$menu_object = menu_load('main-menu');
echo t($menu_object['title']);

?>
</h3>

<?php
$tree = menu_tree_all_data('main-menu');

function output_menu_nested_tree($tree) {
if (count($tree)) {
$output = '<ul class="menu-tree">';
foreach ($tree as $item) {

$menu_link = $item['link'];
if($menu_link['hidden'] != 1) {
$output .= '<li class="menu-term">';
$output .= '<a href="' . $menu_link['link_path'] . '" title="'.$menu_link['link_title'].'">';
$output .= $menu_link['link_title'];
$output .= '</a>';
if (isset($item['below'])) {
$output .= output_menu_nested_tree($item['below']);
}
$output .= '</li>';
}
}
$output .= '</ul>';
}
return $output;
}

$output=output_menu_nested_tree($tree);
echo $output;

?>