Living underground has certain advantages, not only as protection from animals or other enemies, or for avoiding earthquakes. As regards temperature, it is much more stable: at a depth of one metre underground, daily temperature fluctuations are around ± 5ºC, but at 5 metres deep this is less than ± 1ºC. Moreover, inside caves or dugout areas, the temperature tends to be around 17ºC to 23ºC, very near our point of thermal comfort, as opposed to over ground, where temperature varies greatly due to the Earth’s rotation and the effect of sunlight.