public override void ViewDidLoad ()
{
    base.ViewDidLoad ();

    double longitud = -8.756193515625D;
    double latitud = 41.6482883125936;
    CLLocationCoordinate2D coordinates = new CLLocationCoordinate2D(latitud,longitud);

    // Retrieve the placemark on these new coords
    MKReverseGeocoder reverseGeocoder = new MKReverseGeocoder(coordinates);
    ReverseGeocoderDelegate geocoderDelegate = new ReverseGeocoderDelegate();
    reverseGeocoder.Delegate = geocoderDelegate;
    reverseGeocoder.Start();
}


private class ReverseGeocoderDelegate : MKReverseGeocoderDelegate
{
    public ReverseGeocoderDelegate(IntPtr handle) : base(handle) { }

    public ReverseGeocoderDelegate() : base()
    {
    }


    public override void FoundWithPlacemark (MKReverseGeocoder geocoder, MKPlacemark placemark)
    {
        string locationString = placemark.Title;
        if(String.IsNullOrEmpty(locationString))
        {
            locationString = placemark.Locality;
        }
    }

    public override void FailedWithError (MKReverseGeocoder geocoder, NSError error)
    {
    }
}