Display post url under post featured image

I’m trying to display a given post title under each post image (they are positioned in a grid). So far I’m only getting the current page url.

<?php
	  $thumbnails = get_posts('numberposts=15');

	  foreach ($thumbnails as $thumbnail) {
		if ( has_post_thumbnail($thumbnail->ID))
		 {
		echo '<div class="case">';
		echo '<li><a href="' . get_permalink( $thumbnail->ID ) . '" title="' . esc_attr( $thumbnail->post_title ) . '">';
		echo get_the_post_thumbnail($thumbnail->ID, 'large');
		echo '</a></li>';	

		echo '<a href="' . get_post_permalink( $ID ) . '">' ;
		echo get_the_title($ID); '</a>';
		echo '</div>';
		}
	  }
	?>