void Start()
    {
        GameObject worldObjects = new GameObject("WorldObjects");

        truckObjectHolder = new GameObject("TruckObjects");
        truckObjectHolder.transform.SetParent(worldObjects.transform);
        cityObjectHolder = new GameObject("CityObjects");
        cityObjectHolder.transform.SetParent(worldObjects.transform);
        //Each Holder will load prefabs individually for instantiation later
        if (TruckHolder == null)
        {
            TruckHolder = ScriptableObject.CreateInstance <TruckHolder>();
        }

        if (CityHolder == null)
        {
            CityHolder = ScriptableObject.CreateInstance <CityHolder>();
        }

        if (Settings == null)
        {
            Settings = FindObjectOfType <GameController>().Settings;
        }
    }
        public async void AddAsyncName(City city)
        {
            await CityHolder.updateCityWithName(city);

            Cities.Add(city);
        }
        public async void AddAsyncLatLon(City locazioneCorrente)
        {
            await CityHolder.updateCityWithLatLon(locazioneCorrente);

            Cities.Insert(0, locazioneCorrente);
        }