A Polisario fighter sits on a rock at a forward base on the outskirts of Tifariti, Western Sahara, September 9, 2016. At a rocky outpost in Western Sahara, a new generation of soldiers who have never known war are mobilising as tensions resurface in one of Africa's oldest disputes after a quarter century of uneasy peace. (Photo by Zohra Bensemra/Reuters)

Allison Callender and Kent Willis, members of Mekanix Gym, a total wellness center, take a cold plunge in ice after a workout at the gym's Shadow Sanctuary facility during hot weather in Houston, Texas, U.S., July 19, 2023. (Photo by Adrees Latif/Reuters)

Roof-topping enthusiast Daniel Lau takes a selfie with high-rise buildings down below as he stands on the top of a skyscraper in Hong Kong, China on August 15, 2017. A craze that began in Russia has now taken hold in Hong Kong, one of the world's most vertical cities. Mr Lau said he had been inspired by Russian climbers and that he was unafraid of the vertiginous heights he scales. (Photo by ImagineChina/Rex Features/Shutterstock)

Belgian Fran Vanhoutte celebrates as she crosses the finish line at the finals of the women's 500m +D speed skating event, at the World Games 2025, in Chenghdu, China, on Thursday 14 August 2025. This year, the World Games take place from 7 to 17 August. (Photo by Rex Features/Shutterstock)

The American skier Lindsey Vonn celebrates winning the women’s downhill race in the FIS Alpine Ski World Cup on December 12, 2025. She is joined on the podium by Moritz, the competition’s official mascot, named after the Swiss resort in which it is held. (Photo by Denis Balibouse/Reuters)

Argentina's Clara Baiocchi pats Puerto Rico's Alondra Negron as she falls during the women's 3000-meters steeplechase final at the Pan American Games in Santiago, Chile, Saturday, November 4, 2023. (Photo by Fernando Vergara/AP Photo)

Australia's Nicholas Timmings competes in the men's Skeleton World Cup in Altenberg, eastern Germany, on December 3, 2021. (Photo by Tobias Schwarz/AFP Photo)

Spacewalker Mark Vande Hei took his own photograph during the first spacewalk of 2018, on January 23, 2018. These sky-high pictures are better known as “space-selfies”. (Photo by Mark Vande Hei/NASA)