Swift 2 Adding callouts to annotations

I'm having extreme difficulty having callouts added to my annotations. I've removed any attempt at adding the callout from the code below.

The annotations are added at the bottom of the updateVisiblePins function

import UIKit
import MapKit
import CoreLocation
import Foundation

class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {
    @IBOutlet weak var mapView: MKMapView!
    var locationManager = CLLocationManager()
    var landmarkToPass: String!
    var rowIndex: Int!


    struct MyVars {
        static var prevLoc = CLLocation()
        static var region = MKCoordinateRegion()
        static var landmarks = [Landmark]()
        static var landmark: Landmark = Landmark(title: String(), locationName: String(), discipline: String(), coordinate: CLLocationCoordinate2D())
}

    override func viewDidLoad() {
        super.viewDidLoad()

        self.locationManager = CLLocationManager()
        self.locationManager.delegate = self
        self.locationManager.requestWhenInUseAuthorization()
        self.locationManager.startUpdatingLocation()
        self.mapView.showsUserLocation = true
        var landmarks: [Landmark] = [Landmark]()
        loadInitialData()
    }

    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
            var prevLoc = MyVars.prevLoc
            let userLoction: CLLocation = locations[0]
            let distance = calculateDisatnceBetweenTwoLocations(prevLoc, destination: userLoction)
            if prevLoc != userLoction {
                prevLoc = userLoction
                MyVars.prevLoc = userLoction

            if distance > 5 {
                let latitude = userLoction.coordinate.latitude
                let longitude = userLoction.coordinate.longitude
                let latDelta: CLLocationDegrees = 0.05
                let lonDelta: CLLocationDegrees = 0.05
                let span:MKCoordinateSpan = MKCoordinateSpanMake(latDelta, lonDelta)
                let location: CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitude, longitude)
                MyVars.region = MKCoordinateRegionMake(location, span)
                self.mapView.showsUserLocation = true
                self.mapView.setRegion(MyVars.region, animated: true)
                updateVisiblePins()
            } else {
                let latitude = userLoction.coordinate.latitude
                let longitude = userLoction.coordinate.longitude
                let span = mapView.region.span
                let location: CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitude, longitude)
                MyVars.region = MKCoordinateRegionMake(location, span)
                self.mapView.showsUserLocation = true
                updateVisiblePins()
            }
        }
    }


    func calculateDisatnceBetweenTwoLocations(source:CLLocation,destination:CLLocation) -> Double{
        var distanceMeters = source.distanceFromLocation(destination)
        var distanceKM = distanceMeters / 1000
        return distanceKM
    }


    func updateVisiblePins() {
        for (index, landmark) in MyVars.landmarks.enumerate() {
            let landmarkLat = landmark.coordinate.latitude
            let landmarkLon = landmark.coordinate.longitude
            let userLocation = locationManager.location
            let landmarkLocation = CLLocation(latitude: landmarkLat, longitude: landmarkLon)
            let distance = calculateDisatnceBetweenTwoLocations(userLocation!, destination: landmarkLocation)
            if distance < 30 {
                mapView.addAnnotation(landmark)
            } else {
                if rowIndex != nil {
                    if index == rowIndex{
                        self.mapView.addAnnotation(landmark)
                    } else {
                        mapView.removeAnnotation(landmark)
                    }
                }
            }
        }
    }


    func loadInitialData() {
        // 1
        let fileName = NSBundle.mainBundle().pathForResource("PublicLandmark", ofType: "json")

        var data: NSData = NSData()
        do {
            data  = try NSData(contentsOfFile: fileName!, options: [])
        } catch {

        }


        // 2
        var jsonObject: AnyObject!
        do {
            jsonObject = try NSJSONSerialization.JSONObjectWithData(data,
                options: [])
        } catch {

        }

        // 3
        if let jsonObject = jsonObject as? [String: AnyObject],

        // 4
        let jsonData = JSONValue.fromObject(jsonObject)?["data"]?.array {
            for landmarkJSON in jsonData {
                if let landmarkJSON = landmarkJSON.array,landmark = Landmark.fromJSON(landmarkJSON) {
                        MyVars.landmarks.append(landmark)
                }
            }
        }
    }
}

The mapView.delegat = self line needs to be added to viewDidLoad() function.