<div class="container">
<?php query_posts('posts_per_page=30'); ?>
 <?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
 <div class="row">
 <div class="col-sm-4">
<?php if ( has_post_thumbnail()) { $url = wp_get_attachment_url( get_post_thumbnail_id() ); ?>
<img src="<?php echo $url; ?>" alt="<?php the_title() ?>">
  <h3><?php the_title() ?></h3>
 </div><!-- col -->
</div><!-- row -->
 <?php } ?>
<?php endwhile; endif; ?>
</div><!-- container -->

<?php wp_reset_query(); ?>