Ice palace - The Kingdom of Tonophria in the north is beneath the ice. Accessible by tunnels and hidden passages going down, there is nothing but an expanse of ice reminicent of Antartica above. Possibly one of the most interesting Kingdoms in the saga.
The castle -- He didn't know whether to fear, or embrace the sunlight. How rare it shown, and yet, how brightly it lit the shadows. When things are in darkness, secrets can be kept. But light had a strange way of unearthing even the darkest truths.