class Details
{
    public string name { get; set; }
    public int level { get; set; }
    public int map_id { get; set; }
    public List<string> flags { get; set; }
    public Location location { get; set; }
}

class Location
{
    public string type { get; set; }
    public List<float> center { get; set; }
    public float radius { get; set; }
    public float rotation { get; set; }
    public List<float> z_range { get; set; }
    public List<List<float>> points { get; set; }
}

RestClient client = new RestClient();
RestRequest request = new RestRequest("https://api.guildwars2.com/v1/event_details.json");
request.RootElement = "events";

IRestResponse<Dictionary<string, Details>> response = client.Execute<Dictionary<string, Details>>(request);
Dictionary<string, Details> details = response.Data;

Details example = details["703E5B36-63E8-4150-B0E3-68535CBFB144"];