I do not understand why the WC3 validator is flagging this HTML as invalid, the error it reports back is...

''Element ul not allowed as child of element span in this context. (Suppressing further errors from this subtree.)''

I'm using HTML5, and this code is for breadcrumbs.

```
<span class="bread">
    <ul>
        <li><a href="./index.php">HOME</a></li>
        <li>ABOUT</li>
    </ul>
</span>

```