title: How do you explain the result for a new \DateTime('0000-00-00 00:00:00')?
body: <p>Here is a test code:</p>
  
  <pre><code>&lt;?php
  
  ini_set('date.timezone', 'Europe/London');    
  $dt = new \DateTime('0000-00-00 00:00:00');
  
  var_dump($dt);
  </code></pre>
  
  <p>This provides:</p>
  
  <pre><code>object(DateTime)[1]
    public 'date' =&gt; string '-0001-11-30 00:00:00' (length=20)
    public 'timezone_type' =&gt; int 3
    public 'timezone' =&gt; string 'Europe/London' (length=13)
  </code></pre>
  
  <p>Whereas this is not a valid date. I don't understand the returned value, especially the month... can you explain?</p>