Sunlight in the Arctic and Antarctic
At the Earth's south pole the Sun is above the horizon for about six months and below it for six months. Sundials are not much use there for most of the year! On the antarctic circle (latitude 66.5 degrees south), the Sun skims along the horizon all day on mid-winter's day, just touching the horizon even at midday. In between the antarctic circle and the south pole, the number of days with constant sunshine varies from one day to six months. The same of course happens in the arctic, but in reverse. Antarctic summer happens at the same time as arctic winter.
Photograph by Eric Woehler