Void Elements
Some elements shouldn't have content inside them, meaning there's no need for a closing tag, for example breaks or images, since it's hard to see how that would make sense. Another example is the meta element. In XHTML(an ancestor of HTML5) we would include a "/" at the end before the final ">" that closed the tag
All HTML5 void elements have only one tag, with no slashes.
break is <br>
image is <img src="images/me.jpg" alt="picture of myself">
In XHTML these are called empty elements and have a few differences.
If you see an element with only one tag and a "/" before the tag-closing ">" you can
simply get rid of the "/" (and probably a space before it) to make it standard HTML5