<div class="places-nav">
<?php $args = array('post_type' => 'trips');
    $loop = new WP_Query( $args );

    //Display the contents
    while ( $loop->have_posts() ) : $loop->the_post(); ?>
        <a href="#" onclick="get_post_content(<?php the_ID(); ?>);"><h1 class="entry-title"><?php the_title(); ?></h1></a>
    <?php endwhile;?>
</div>