Chloe Kim
At 14, she became the youngest athlete in history to win a Winter X Games gold medal, when she took the Super Pipe title in Aspen, beating American legend Kelly Clark in the process. It was a particularly satisfying success for Kim, who lost to Clark at the 2014 X-Games and had to settle for the silver medal. She had also been too young to compete in the 2014 Sochi Winter Olympics, but made a massive impact in 2015. The US magazine Time named her in their annual list of the ‘30 Most Influential Teens of 2015’ which included actors, scientists and President Obama’s daughter.