This tag forces the browser to display everything exactly how it is typed in the HTML document. What this means is you can type a large number of spaces, and have all of it show, instead of being skipped by the browser like normal. They can happen when you leave that page or enter it. The value ranges from 1 to 23. Try different numbers out yourself to see what kind of results you get.
Activities Create a page with a border all the way around it.
Create a page with a square at the top that automatically loads a page with hidden messages in it after 8 seconds. Make an indented paragraph, where every line is indented the same and a second paragraph where every line's indent is 5 greater than the line before it.