My YouTube video wont show in iframe
<p>Here is the code I entered in my HTML</p>

<pre><code>&lt;iframe width="640" height="360" src="https://www.youtube.com/watch?v=ZwKhufmMxko"&gt;
&lt;/iframe&gt;
</code></pre>

<p>The video frame will show, but the actual video won't load or even show up. 
I have tried waiting, so it shouldn't be a loading issue.</p>

<p>I also am currently only using HTML and CSS </p>

<p>Any ideas on how I can get this to work? </p>