Most HTML elements have an opening tag and a closing tag.
Opening tags look like this: <h1> and Closing tags look like this: </h1>.
Note that the only difference between opening and closing tags is that closing tags have a slash after their opening angle bracket.
There are also some HTML elements that are self-closing.
For example, the image tag <img /> and the input tag <input />.
Try it here! http://www.freecodecamp.com/challenges/say-hello-to-html-elements