You can quickly add a sitemap to a page or post by using the sitemap shortcode, in any theme. Just add this shortcode:

[sitemap]

The shortcode will display an outline of all your site’s pages in a hierarchical bulleted list, following any parent/child relationships set in Page Attributes.

You can also use the sitemap shortcode in a text widget, although the display may not be bulleted or indented, depending on how your theme is designed.

View the sitemap shortcode in action on the Big Brother theme demo.