     override open func didReceiveMemoryWarning() {
         super.didReceiveMemoryWarning()
 
-        mapView.removeAnnotations(mapView.annotations)
+        mapView.removeAnnotations(removableAnnotations)
     }
 
     // MARK: Implementation
+
+    fileprivate var removableAnnotations: [MKAnnotation] {
+        return mapView.annotations.filter(isNonSelectedPlacemark)
+    }
 
     /**
      Small helper necessitated by `CLLocationCoordinate2D` not being

            span: MKCoordinateSpanMake(degrees, degrees)
        )
        mapView.setRegion(region, animated: animated)
    }

    // MARK: Actions

     Doing so would fail with a warning about 'un-added' annotations.
     */
    fileprivate func updateAnnotations() -> [MKAnnotation] {
        mapView.removeAnnotations(removableAnnotations)
        var addiblePlacemarks = resultsViewController.mapItems.map { $0.placemark }
            .filter(isNonSelectedPlacemark)
        mapView.addAnnotations(addiblePlacemarks)
        return addiblePlacemarks
    }

    /**
