An image map is a normal image on a website which has different clickable regions which take you to different pages. Image map functionality allowed polygons of an image to be defined as independent hyperlinks.

<!-- References an image map -->
<img src="image.png" usemap="#map1" />

<map id="map1" name="Map 1">
  <!-- An example of a rectangular area over an image -->
  <area shape="rect" coords="10,10,100,100"
        href="/foo"
        alt="Go to the Foo page"/>

  <!-- An example of a circular area over an image -->
  <area shape="circle" coords="50,50,200"
        href="/bar"
        alt="Go to the Bar page"/>

  <!-- An example of an arbitrary polygon over an image -->
  <area shape="poly" coords="10,10,100,10,100,100,10,100"
        href="/baz"
        alt="Go to the Baz page"/>

  <!-- Fallback if no other area matches -->
  <area shape="default"
        href="/default"
        alt="Go to the Default page"/>
</map>