POLAR

Though they are – literally – poles apart, the Arctic and Antarctica offer similar challenges and rewards. At the earth’s extreme north lies the Arctic, a region mainly covered with sea or shimmering ice, but also encompassing parts of Alaska, Greenland, Russia and Canada. Its outer limit, the Arctic Circle, is home to polar bears, seals, walruses and narwhals, and is defined as the region where the sun does not rise on the winter solstice and does not set on the summer solstice. At the globe’s far south lies a corresponding zone, the Antarctic Circle, which rings a huge, ice-covered landmass, Antarctica – coldest, driest, and windiest of the continents – where penguins and albatrosses break up the snowy vistas.