An expedition is attempting to be the first to use a bike to reach the South Pole. It will mean tackling some of the most extreme conditions on the planet. So how can a bike manage it?
Snowdrifts, blizzards, rutted ice, altitude sickness, frostbite and snow blindness. They're hardly the odd speed bump, tree root or wayward pedestrian a cyclist usually faces on a bike ride, but this isn't an average journey.
Blue Peter presenter Helen Skelton is hoping to become the first person to use a bike to reach the South Pole. She is attempting to travel 500 miles (805km) across Antarctica and will cycle for large parts of it, as well as snowkiting and walking. She hopes to complete the trek for Sport Relief in 20 days.
More at the BBC.