diff --git a/public/index.html b/public/index.html
index 05b4160..bd87a71 100755
--- a/public/index.html
+++ b/public/index.html
@@ -17,6 +17,9 @@
   <nav id="primaryNav" class="primary-nav"></nav>
 </header>
 
+<!-- HORIZON LAYER: Emergent Sub-Navigation -->
+<nav id="subNav" class="sub-nav"></nav>
+
 <aside id="sidebar">
   <div class="sidebar-header">
     <h3>Contents</h3>