How to keep vehicles warm in the Antarctic
British explorer Sir Ranulph Fiennes is preparing for his latest adventure - to be the first person to trek on foot across Antarctica in the middle of winter.
Although the attempt is only being announced on Monday, the BBC's Matthew Price has been following his preparations for some months.
Among the many challenges faced by the team is how to keep their vehicles from freezing while stationary overnight in temperatures of -70C.
Matthew Price caught up with the team at a vehicle testing ground in the town of Arjeplog, close to the Arctic Circle, in Sweden, to see their solution.