Embedding Other Sites on a Page

This is commonly done with something called an iFrame. The iFrame tag will will have an src link to an external site, which the iFrame will reder within a block or window of the specified size

The below iFrame is described thus:

iframe src="//www.shipmap.org" style="width: 100%; height: 600px; border: 0" frameborder="0"
Created by London-based data visualisation studio Kiln and the UCL Energy Institute

To learn more HTML/CSS, check out these tutorials!