A smokejumper leaps from an airplane during a training flight above Winthrop, Washington, U.S., June 30, 2016. On a 100-degree day in early June, eight experienced firefighters did sit-ups in a semicircle training to parachute into a wildfire. Better known as “rookie candidates”, they were determined to make it through the five-week program at North Cascades Smokejumper Base in Winthrop, Washington, where the first experimental jumps occurred in 1939. (Photo by David Ryder/Reuters)

This brave swimmer certainly has a brrracing workout each weekend she skinny dips in one of the coldest rivers in Europe which regularly plummets to temperaturess of –9C. Inna Vladimirskaya, 32, strips off on the banks of the Dnieper river, in Kiev, Ukraine, every Sunday morning, and takes a swim after jogging along the snowy banks of the river in the nip. (Photo by David Tesinsky/Caters News Agency)

David Colturi of the USA dives from the 27 metre platform during the fifth stop of the Red Bull Cliff Diving World Series in Polignano a Mare, Italy on August 28 2016. (Photo by Dean Treml/ANSA/Red Bull Press Office)

A history enthusiast, dressed as a soldier, marches before the re-enactment of Napoleon's famous battle of Austerlitz near the southern Moravian town of Slavkov u Brna, Czech Republic December 3, 2016. (Photo by David W. Cerny/Reuters)

British model Jourdan Dunn and London-based hair stylist Issac Poleon attend an event to celebrate the Maximilian Autumn/Winter 2022 collection in The Green Room at The Londoner Hotel on February 20, 2022 in London, England. (Photo by David M. Benett/Dave Benett/Getty Images for The Londoner Hotel)

China goalkeeper Zhou Jiaying blocks a shot against Japan during a preliminary round women's hockey game at the 2022 Winter Olympics, Sunday, February 6, 2022, in Beijing. (Photo by Petr David Josek/AP Photo)

A supporter of presidential candidate and former chairman of the NATO Military Committee and Czech Army General Petr Pavel hands out leaflets, ahead of a direct presidential election that will start on January 13, in Prague, Czech Republic on January 5, 2023. (Photo by David W. Cerny/Reuters)

Sean Tschigerl #19 of the Calgary Hitmen, Tyson Galloway #22 of the Calgary Hitmen and David Adaszynski #17 of the Calgary Hitmen jump into the stuffed toys after a goal in the first period on the Prince Albert Raiders during the annual Teddy Bear Toss at the Scotiabank Saddledome on December 03, 2023 in Calgary, Alberta. (Photo by Leah Hennel/Getty Images)