IFrame Tag
Websites in websites
The Iframe tag is used to include outside websites in another website, which can be usefull for a wide variety of resource-implementations. For example, to implement a youtube video, you would use an iFrame tag! To use the Iframe tag, include

src="http://www.websiteurlhere.com"
in the opening tag. Additionally, you can choose to set a height and width for the Iframe tag by simply defining the dimensions in the opening tag:

<iframe src="http://www.wisdombytes.com" height="500px" width="300px"></iframe>
IFrame tag in an example