SharePoint 2013 introduces Managed Navigation which allows you to drive SharePoint navigation based on managed metadata. Managed metadata is hierarchal in nature and is managed at the site collection level.
In many cases, people wanted more control over the site navigation than SharePoint provided out of the box. Publishing sites provide great options for dynamically displaying the navigation based on the site’s hierarchy, but what if you want to display navigation based on metadata?
When you tie navigation to this hierarchy, you can be sure that every site in the site collection will subscribe to the same structure. When you need to update the hierarchy, you update it for the entire site collection, and every site automatically updates navigation as well. You access the Navigation settings page from the Look and Feel section of Site Settings.
If you still need more navigation control, you can always bring in developers. SharePoint is built on ASP.NET and allows developers to use special controls for modifying navigation. Because this involves writing code, it’s best left to professional developers — but you should at least know it’s possible.