gistfile1.cs

{
    public class Estado
    {
        public int id { get; set; }
        public string nome { get; set; }
        public string uf { get; set; }
    }

    public class City
    {
        public int id { get; set; }
        public string nome { get; set; }
        public bool ativo { get; set; }
        public double latitude { get; set; }
        public double longitude { get; set; }
        public Estado estado { get; set; }
        public string bandeira { get; set; }
        public string brasao { get; set; }
        public string foto_apresentacao { get; set; }
        public string data_fundacao { get; set; }
        public string apresentacao { get; set; }
        public string apresentacao_ingles { get; set; }

        public void GetCities()
        {
            try
            {
                WebClient client = new WebClient();
                client.DownloadStringCompleted += client_DownloadStringCompleted;
                client.DownloadStringAsync(new Uri("http://xxxx.yyy.zz"));
            }
            catch (Exception)
            {
            }
        }

        void client_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        {
            var toor = JsonConvert.DeserializeObject<IList<City>>(e.Result);
        }
    }
}