I had a problem to get the custom Views for the Annotations to work. I've watched the videos multiple times, but there would not appear a button when I tapped my pins. After few minutes of research I figured out that I have to assign my UIViewController as the delegate for my mapView. So if you have problems, try adding mapView.delegate = self to the top of your viewDidLoad() method.

Thank you! I was stuck on this problem for a little bit, thankful that I found this after some googling.

-Mark

It also can be done in Interface Builder. Select Map View then "Connection Inspector". Drag delegate to our ViewController on the left.