Paramilitary policemen carry tyres as they take part in a training session in Zhangye, Gansu Province, China, March 1, 2016. (Photo by Reuters/Stringer)

A man and a girl take a dip in icy waters during celebrations for the Orthodox Epiphany in the Sea of Japan in the far eastern city of Vladivostok, Russia, January 19, 2016. Orthodox believers mark Epiphany on January 19 by immersing themselves in icy waters regardless of the weather. (Photo by Yuri Maltsev/Reuters)

Clearing skies await a tripod-toting photographer looking for a spot to capture the early-morning light at Portland Head Light, Thursday, January 17, 2013, in Cape Elizabeth, Maine. (Photo by Robert F. Bukaty/AP Photo)

A performer is seen floating in mid-air as he holds onto a moving bus during the International Magic Festival in Luoyang, Henan province, China September 11, 2016. (Photo by Reuters/China Daily)

A winter swimmer, wearing a Santa Claus hat to celebrate the upcoming Christmas, reacts as he plays on a frozen lake at a park in Shenyang, Liaoning province, December 22, 2014. The characters on the hat read: “Shenyang Winter Swimming”. (Photo by Reuters/Stringer)

These two young siblings appear to cling on to a tree for dear life and even hold hands as they learn the ropes of climbing, on June 25, 2013. (Photo by Tim Fitzharris/Minden/Solent)

Local villagers fall onto the ground from an ox-cart as they ride to rid evil spirits from their village at Pring Ka-ek village, Cambodi. (Photo by Heng Sinith/AP Photo)

“The Net thrower”. The fisherman are conducting activities on Situgunung Lake. Photo location: Situgunung lake, Sukabumi, West Java, Indonesia. (Photo and caption by Dody Kusuma/National Geographic Photo Contest)