On a long web page, it may be useful to have links which take you to a specific point further down the page, or back up. To do this, first of all you create an anchor, which is like a bookmark, and then you make a link to it from somewhere else on the page.
The code for an anchor is:
<a name="thames"></a>
where "thames" is a name that you make up.
Link to this anchor with another <a> tag like this:
<a href="#thames">Go to Thames</a> (note the '#' symbol)
You can also link to this anchor from another page, by using the form:
<a href="page1.html#thames">Link to Thames page</a>
where "page1.html" is the page containing the anchor.