A British adventurer has become the first blind person to trek to the South Pole.
During his 39-day expedition, Alan Lock, 31, suffered howling winds, temperatures of -35C and whiteout blizzards.
The amateur explorer completed the 600-mile journey to raise money for the Sightsavers charity.
Speaking from the South Pole, Mr Lock said: "It feels amazing to have made it to the South Pole, what an adventure.
"The high point is having the opportunity to make this expedition in the first place. Reaching the pole, having been only one of a handful of people to have ever walked here, is a fantastic experience.
"There have been difficulties with the terrain but this has all been made possible for me by my great team members.
The trip, which started on November 22, has raised £15,000 so far for the Sightsavers charity, which aids blind people in the developing world, and San Francisco-based Guide Dogs for the Blind.
Mr Lock, from Clevedon, Somerset, undertook the Polar Vision trek accompanied by two sighted team mates Andrew Jensen and Richard Smith, whom he met while studying for an MBA in the United States, plus guide Hannah McKean.
Having been forced to halt his naval career after losing all but his peripheral vision, Mr Lock now works in telecommunications.
But since losing his sight, he has completed 10 marathons, including the 151 mile Marathon Des Sables in the Sahara Desert. He has been to a number of mountain summits including the highest mountain in Europe, Mt Elbrus, and in 2008 Alan set a Guinness World Record when he became the first visually impaired person to row across the Atlantic Ocean.
The Polar Vision team underwent intensive training that included a camp in Iqaluit, Canada, where they spent a week traversing the ice pack near the Arctic Circle on skis, and dragging tyres attached to their waists along beaches and parks back home to develop the muscles needed to pull the sleds.
"Trekking for over nine hours each day we have been losing up to 9,000 calories a day," Mr Lock said.
"We've also suffered many falls and bruises whilst trekking across the rough terrain as there are many big drops and jumps which I've relied on my teammates to guide me through."
Caroline Harper, the chief executive of Sightsavers, added: "Sightsavers is incredibly grateful and honoured that Alan has chosen to support our work to eliminate avoidable blindness in the developing world.
"By taking on such a colossal challenge and raising money for Sightsavers' work, they will help to transform the sight and lives of some of the world's poorest people."