diff --git a/doc/manual/source/_templates/navigation.html b/doc/manual/source/_templates/navigation.html
index 93a8f5010..06f8a6882 100644
--- a/doc/manual/source/_templates/navigation.html
+++ b/doc/manual/source/_templates/navigation.html
@@ -9,3 +9,7 @@
     {% endfor %}
 </ul>
 {% endif %}
+<hr />
+<ul>
+    <li class="toctree-l1"><a href="{{pathto('genindex.html', 1)}}">Index</a></li>
+</ul>