The polar and circumpolar regions present a physical and social environment that greatly challenges human habitation. The challenges include not only the physical environmental conditions such as the hostile climate, high attitude, extreme light-dark cycle, low humidity and lack of sensory stimulation, but also social environmental conditions such as prolonged isolation from family and friends, confinement in small groups and lack of privacy. The harsh environment makes surviving in the polar and circumpolar regions no less difficult than surviving in undersea or space habitats.