Getting ready

To achieve this recipe, you need a 404.php file. Most WordPress themes actually feature this kind of page. If, for some reason, your theme doesn't feature such a page, simply create a php file named 404.php and upload it to your wp-content/themes/yourtheme directory. You don't have to add a Page template directive—WordPress automatically recognizes a file named 404.php as a page designed to be displayed if a 404 error occurs.

In this example, we are using the 404.php file from the default WordPress theme. If you open the file, you'll find the following code:

<?php get_header(); ?>
    <div id="content" class="narrowcolumn">
    <h2 class="center">Error 404 - Not Found</h2>
    </div>
<?php get_sidebar(); ?>
<?php get_footer(); ?>

As you can see, this page does nothing except inform the user that nothing was found at the particular URL. Let's enhance it to help the visitor looking for some content, by displaying archives, categories, and a link to the blog homepage.

How to do it...

How it works...

WordPress features an interesting template hierarchy mechanism. When a 404 error appears, WordPress automatically looks for a file named 404.php. If such a file exists, it is displayed. Otherwise, the 404.php file is displayed page .

In the 404.php file we have displayed our blog's monthly archives and categories to make sure that the reader will find the content that he's looking for.

There's more...

In this recipe, we have seen how to create a useful 404 page. However, did you know that some bloggers also enjoy creating funny 404 pages? For example, the 404 error page of my blog Cats Who Code, features a picture of a cat trying to repair a PC with the caption, "There's a problem, but someone is fixing it".

For a list of funny an unusual 404 pages, you should take a look at the following link: http://blogof.francescomugnai.com/2008/08/the-100-most-funny-and-unusual-404-error-pages/