Unrecognized selector sent to instance?

I have seen that a few others have had this problem as well. I'm trying to follow a tutorial online that shows how to create animated pins on a MapView.

I have implemented the code as shown in the tutorial and the project builds fine except I receive this exception:

-[MKPointAnnotation iconN]: unrecognized selector sent to instance

I have a subclass of 'MKPinAnnotationView' and in the .m file I create this method:

- (void)setAnnotation:(id<MKAnnotation>)annotation {

    [super setAnnotation:annotation];



    //Place *place = [[Place alloc] init];

    Place *place = (Place *)annotation;





    //The following line is where the program sends "SIGABRT"

    icon = [UIImage imageNamed:[NSString stringWithFormat:@"pin_%d.png", [place.iconN intValue]]];

    [iconView setImage:icon];

}

Here are a few parts from my "model" which is called Place.h/.m. Here is where I create the property for 'iconN'.

@property (retain, nonatomic) NSNumber *iconN;

And here I synthesize it:

@synthesize iconN = _iconN;

Any help is greatly appreciated.

EDIT: Here is the Place.h and Place.m

#import <MapKit/MapKit.h>

#import <CoreLocation/CoreLocation.h>





@interface Place : NSObject <MKAnnotation> {

    CLLocationCoordinate2D coordinate;

    NSString *title;

}



@property (retain, nonatomic) NSNumber *iconN;

@property (nonatomic, copy) NSString *title;

@property (nonatomic) CLLocationCoordinate2D coordinate;



- (id)initWithLong:(CGFloat)lon Lat:(CGFloat)lat iconNumber:(NSNumber *)iconNumber;



@end

And the Place.m

#import "Place.h"



@implementation Place

@synthesize coordinate;

@synthesize iconN = _iconN;

@synthesize title;



- (id)initWithLong:(CGFloat)lon Lat:(CGFloat)lat iconNumber:(NSNumber *)iconNumber {

    self = [super init];

    if (self) {

        coordinate = CLLocationCoordinate2DMake(lat, lon);

        self.iconN = iconNumber;

    }



    return self;

}



- (NSString *)title {

    return [NSString stringWithFormat:@"Bus: %d", [self.iconN intValue]];

}



- (NSString *)subtitle {

    return [NSString stringWithFormat:@"bus[%d] from database.", [self.iconN intValue] - 1];

}





@end