As you saw in the app tour, many screens have a navigation bar at the top of the screen. To get this, you will embed the view controller of the Explore and Map scenes in a navigation controller. This will make navigation bars appear at the top of the screen when the Explore and Map screens are displayed:

1. Click Explore Scene in the document outline:

2. Choose Editor | Embed In | Navigation Controller:

3. A Navigation Controller Scene appears between the Tab Bar Controller Scene and the Explore Scene:

4. Build and run your app. Note that the Explore screen now has a navigation bar:

Embedding a view controller in a navigation controller adds that view controller to the navigation controller's viewControllers array. The navigation controller then displays the view controller's view on the screen. The navigation controller also displays a navigation bar at the top of the screen. If you tap the Map button in the Tab Bar, you'll see the Map screen does not have a navigation bar yet.

5. Click Map Scene in the document outline:

6. Choose Editor | Embed In | Navigation Controller:

7. A Navigation Controller Scene appears between the Tab Bar Controller Scene and the Map View Controller Scene:

Build and run your app. Both screens now have a navigation bar:

The Tab Bar buttons can switch between the Explore and Map screens, and each screen now has a navigation bar. The button titles are correct but the buttons themselves do not have icons. To get the button icons, you will add a file containing all of the graphics assets required for your project in the next section.