Igloo

arctic · shelter · engineering

Built from snow blocks. Igloos are constructed by cutting rectangular blocks from hard-packed snow and stacking them in a spiral dome shape. This design is incredibly smart because the dome shape distributes weight evenly and keeps the inside warm.

Stays warmer inside. Even though it's made of ice, an igloo's thick snow walls trap heat inside, and the dome shape prevents cold air from settling on people. A small lamp or body heat can warm the inside to surprisingly comfortable temperatures.

Traditional Inuit shelter. Indigenous peoples of the Arctic, particularly the Inuit, built igloos as temporary shelters during hunting trips where trees were scarce and snow was plentiful. They were practical solutions for survival in one of Earth's harshest environments.

Entrance tunnel trick. The entrance to an igloo is usually built lower than the inside sleeping area. This design means cold air naturally sinks down into the entrance tunnel and stays out of the main living space, keeping people warmer.