A few HTML elements

<h1>Headline 1</h1>
<h3>Headline 3</h3>
<h5>Headline 5</h5>
<hr />
<p>Lorem <em>ipsum</em> dolor <strong>sit</strong> amet, consetetur sadipscing elitr,<br />sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.</p>
<p><a href="https://en.wikipedia.org/wiki/HTML" target="_blank" title="Go to Wikipedia">External Link</a></p>
<hr />
<ol>
    <li>Firstly</li>
    <li>Secondly</li>
</ol>
<ul>
    <li>This</li>
    <li>That</li>
</ul>
<hr />
<button>Click here and nothing will happen</button>