In the far north, where wood was scarce and solid shelter essential for survival, several unique and innovative architectural styles were developed. One of the most famous is the igloo, a domed structure made of snow, which has highly insulative properties. In the summer months, when the igloos melted, tents made of seal skin, or other hides, were used. The Thule adopted a design similar to the pit houses of the BC interior, but because of the lack of wood they instead used whale bones for the frame.