Which is the only continent with no permanent human residents?

Antarctica. Between one and five thousand people are there at any time depending on the season, all of them on rotation at research stations, and nobody's home address is the continent. It is also the only one with no native population and no country: the Antarctic Treaty of 1959 froze all territorial claims and reserved the place for science, and it has held ever since, which is a better record than most treaties manage.

It is the coldest, windiest and - by precipitation - one of the driest places on Earth, holding about 90 per cent of the world's ice and something like 70 per cent of its fresh water. The lowest natural temperature ever recorded, minus 89.2 degrees, was measured at Vostok Station in 1983.

Two governments have made a point of the residency question for political reasons. Argentina flew a pregnant woman in so a child would be born on the continent in 1978, and Chile followed with a small settlement including families and a school. Both were staking a claim rather than starting a town, and the treaty means neither counts for anything.