 HTML, the foundation of the internet. One of the first programming languages that you will learn as a WordPress developer is HTML. In this lesson, you'll learn what HTML is, how it's used in WordPress, and where to find more information on writing HTML. HTML is synonymous with the web. The originator of the internet designed HTML to be used to create web pages. Whenever you visit a website in a browser, whether it's one of the biggest news portals in the world or your local nonprofit, the document you are viewing is written in HTML. HTML stands for Hypertext Markup Language and is used to describe the structure of a web page. HTML is made up of elements. Elements are the building blocks of HTML documents. An HTML element usually has a start tag, an end tag, and some content in between. Here is an example of an HTML document. In this example, the HTML tag at the top of the page is the start tag. And the HTML tag at the bottom of the page is the end tag. Notice that the end tag starts with a forward slash. The content in between these tags is the content of the HTML element. HTML elements can also be nested inside each other. In this example, the head element is nested inside the HTML element. And the title element is nested inside the head element. HTML elements are semantic, which means that each tag has a specific meaning and should be used in a specific way. For example, the h1 element is a heading element. And the p element is a paragraph element. HTML elements can also have attributes. Attributes are used to provide additional information about an element. In the example, the body element has an attribute called class with a value of main. Certain elements allow you to include media, such as images, audio, and video. In the example, the image element is used to include an image on the page. The source attribute of the image element is used to specify the location of the image. And the alt attribute is used to provide alternative text for the image. HTML elements can also be self-closing. In the example, the image element is self-closing. And you will notice that it doesn't have an n tag. When you visit a web page in a browser, the browser reads the HTML document and displays the content in the browser window. The browser reads the HTML document from top to bottom and left to right. By default, each of the elements is displayed in a different way. For example, the h1 element is displayed as a heading. And the p element displayed as a paragraph. HTML is used everywhere across a WordPress site, from the dashboard to the theme that powers the front-end. Even plugins make use of HTML to display content. When writing HTML, it's important to write accessible HTML. Accessible HTML is HTML that is written in a way that makes it easy for people with disabilities to use. For example, if you're using an image tag to display an image or a logo, you should always include alternative text with the image. This allows people who are using screen readers to understand what the image is. Additionally, you should also always use semantic HTML elements and use them in the correct way. For example, if you're creating a heading, you should use a heading element and not a paragraph one. For more information about writing HTML and making sure your HTML is accessible, you can visit the following online resources. On the Mozilla Developer Network, there is a section on HTML, as well as a section on HTML for accessibility. Then on the Learn Web Dev site, there is a course on HTML and a course on accessibility. And finally, there is the Responsive Web Design course on Free Code Camp.