Lsitar Categorias e Posts

Fiz aqui e deu certo:

<?php
	$categories = get_categories( array( 'parent' => 0 ) );

	foreach( $categories as $category ) :
		echo "<br>Cat: " . $category->name;

		$subcategories = get_categories( array( 'parent' => $category->term_id ) );

		foreach( $subcategories as $subcategory ) :
			echo "<br>Sub: " . $subcategory->name;
			$posts = new WP_Query( array( 'cat' => $subcategory->term_id ) );

			while($posts->have_posts()) : $posts->the_post();
				echo "<br>Post: "; the_title();
			endwhile;			

		endforeach;
	endforeach;
?>