In a major new Herald podcast series, Detour: Antarctica, Thomas Bywater goes in search of the white continent's hidden stories. In this accompanying text series, he reveals a few of his discoveries to whet your appetite for the podcast. You can read them all, and experience a very special visual presentation, by clicking here. To follow Detour: Antarctica, visit iHeartRadio, or wherever you get your podcasts.
A new book suggests that Antarctica sends its visitors mad.
Madhouse at the End of the Earth deals with the ill-fated ship the Belgica, whose crew were trapped in pack ice over the winter of 1898-99.
Among them was first mate Roald Amundsen, who would go on to be the first person to reach the South Pole in 1912. However, his earlier expedition was almost prematurely ended, by freezing temperatures, malnutrition and "polar madness".
"People who go mad in the Antarctic tend to go mad in similar ways," says author Julian Sancton.
Two of Amundsen's crewmates, Belgian Jan van Mirlo and Norwegian boatswain Adam Tollefsen, experienced an episode of shared psychosis, striking them deaf and mute.
On recovering his voice the first thing van Mirlo said was that he intended to kill the captain. Tollefsen became evasive, in fear of his colleagues.
Amundsen wrote that other colleagues suffered "strange symptoms, today which are indicative of insanity", hallucinations and delusions. One crew member had to be stopped from walking into the polar interior, claiming he was walking back to Antwerp.
After 11 long months, the crew were eventually free to return to Belgium and - theoretically - their senses.
However, Sancton says there's a through-line between this episode and other cases of isolation and hysteria in north and south polar regions.
In Greenland, the Inuit have a word for the winter madness - pibloktoq. It's a seasonal disorder that can drive visitors to walk into the Arctic tundra or "scream and tear off clothing".
Today, personnel due to spend winter with the US and New Zealand Antarctic Programmes are screened for psychological fitness before visiting polar bases.
"Winter-over" crew describe disrupted circadian rhythms and hormonal balances, and brain-fog that depresses their activities during the six month darkness.
A study of 313 men and women at McMurdo Station found that 5.2 per cent of base crew had suffered from some degree of psychiatric disorder.
• Madhouse at the End of the Earth by Julian Sancton is published by Penguin.
Detour: Antarctica is a New Zealand Herald podcast. You can follow the series on iHeartRadio,Apple Podcasts, Spotify or wherever you get your podcasts.