An Igloo
An igloo is a structure which is built from blocks of solid snow. They are carefully shaved and placed to fit in the best positions. Igloos are closely associated with Inuit culture. Many Native North American people built igloos, some of which were quite large and elaborate. Igloos can still be seen in the far reaches of North America today. An igloo may also be referred to as a snow house. A classical igloo is dome-shaped. The roof has a small hole for airing, and the door is dug into the snow so that it is lower than the igloo itself. This creates a cold trap, ensuring that the temperature inside the igloo stays relatively warm. In fact, some igloos get quite temperate inside and the uses of heated stones raise the inner temperature. Making an igloo is rather remarkable. The blocks are cut from snow which has been heavily compacted, ensuring that they will be strong, and the structure is built without the use of mortar or supports. Once the igloo is finished, the people inside actually contribute to its strength and solidity, because heat causes the inside blocks to start melting, while the cold refreezes the melted water, creating a smooth sheet of ice which further insulates the igloo.
