A heat-stressed koala waits as a resident pours water on its back on December 19, 2015 in Adelaide, Australia. Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days. (Photo by Morne de Klerk/Getty Images)

National Geographic photographer Steve Winter has spent most of his adult life shooting wild cats. Photo: A 14-month-old cub, cooling off in a pond, is riveted by a deer that appeared near the shore. Tigers are powerful swimmers; they can easily cross rivers four to five miles wide and have been known to swim distances of up to 18 miles. (Photo by Steve Winter/National Geographic)

“One in Eight Hundred” by Mario Wezel, from Germany, is the winner of the “People” category. The title refers to the odds given to Martin and Karina at their prenatal screening before their daughter, Emmy, was born. The five-year-old from Denmark has Down's Syndrome. (Photo by Mario Wezel/Sony World Photography Awards)

A woman is assisted by medical personnel during a celebration in the Mission District in San Francisco, California October 29, 2014. The San Francisco Giants beat the Kansas City Royals 3-2 on Wednesday to win their third World Series title in five seasons. (Photo by Robert Galbraith/Reuters)

In this composite image (top) flooding is seen in the Toowoomba central business district on January 10, 2011 and (bottom) the same location as seen on January 5, 2012 in Toowoomba, Australia. January 10 marks the one year anniversary of the inland tsunami that devestated southern Queensland's Lockyer valley killing 23 people. (Photos by Dan Proud (top) and Lisa Maree Williams (bottom) /Getty Images)

Ahmad Sayed Rahman, a five-year-old Afghan boy who lost his right leg when he was hit by a bullet in the crossfire of a battle, dances with his prosthetic leg at the International Committee of the Red Cross (ICRC) hospital for war victims and the disabled, in Kabul on May 7, 2019. (Photo by Wakil Kohsar/AFP Photo)

Tom Wilder, 17 from Kent, dives in the mud at the Glastonbury Festival site at Worthy Farm, Pilton on June 23, 2011 in Glastonbury, England. Music fans had to brave more rain today at the five-day festival which opened yesterday. This year the festival will feature headline acts U2, Coldplay and Beyonce. The festival, which started in 1970 when several hundred hippies paid 1 GBP to watch Marc Bolan, has grown into Europe's largest music festival attracting more than 175,000 people over five days. (Photo by Matt Cardy/Getty Images)

A super flexible schoolboy has become a limbo legend - by roller-skating under 39 cars in a row. It took six-year-old Gagan Satish just 29 seconds to cover a distance of nearly 70 metres with his face just five inches from the ground. (Photo by Arkaprava Ghosh/Barcroft Media India)