This year is one for polar anniversaries. It was fifty years ago this summer that the United States' nuclear-powered submarine Nautilus successfully made an underwater crossing beneath the polar ice cap from the Bering Strait (between Alaska and Russia) to the Norwegian Sea, becoming in the process the first sea-going vessel to reach the North Pole. If the Nautilus venture (oddly dubbed 'Operation Sunshine' by the US military) represented the triumph of technology over environment, other anniversaries this year commemorate a more traditional form of polar endeavour.

The British explorer Wally Herbert embarked in February 1968 on his long walk across the Arctic. In an extraordinary journey that lasted fifteen months and had echoes of an earlier heroic age of polar exploration, Herbert made landfall in northern Svalbard, having trudged all the way from Alaska over shifting and often perilous Arctic ice.