Kalum Den is a castle-like structure built into the side of the dormant volcano, Mount Vanth. It looks quite big even from the outside, but it extends deep into the mountain itself, making it even larger than it appears. At the front of the den is an open-air courtyard that's used as a place for flights to assemble before they fly. For that reason it's very large. Its floor is made up of worn down stone slabs and it's surrounded by high stone walls with a guarded port-cullis protecting the front entrance.