A competitor reacts as she emerges from the water during the Tough Guy event in Perton, central England, January 26, 2014. The annual Tough Guy race – “the toughest race in the world” – at Perton in Staffordshire. Tough Guy claims to be the world’s most demanding one-day survival ordeal. First staged in 1987, the Tough Guy Challenge has been widely described as one of the hardest races of it’s type with up to one-third of the starters failing to finish in a typical year. (Photo by Darren Staples/Reuters)

Yak near Yamdrok lake, Tibet. It is a long-haired bovinae found throughout the Himalayan region of south Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia. The Tibetan economy is dominated by subsistence agriculture. Due to limited arable land, the primary occupation of the Tibetan Plateau is raising livestock, such as sheep, cattle, goats, camels, yaks, dzo, and horses. The Tibetan yak is an integral part of Tibetan life. (Photo by Dennis Jarvis)

Two office workers wearing summer kimonos Yukata look at paper lanterns as they visit on the eve of Mitama Matsuri, a summer festival at Yasukuni Shrine in Tokyo, Japan, 13 July 2015. About 300,000 people visit the shrine decorated with about 30,000 lanterns during the three-day summer festival aiming at comforting souls of dead, especially for the war dead. The festival is after Japan's Buddhist custom to honor and comfort souls of family's ancestors. (Photo by Kimimasa Mayama/EPA)

A woman takes part in the Watermelon Games at the 55th annual California Watermelon festival in Los Angeles, California on July 29, 2017. The day has become a tradition because watermelons have long been the prized crop of the eastern San Fernando foothills. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

Revellers battle with tomato pulp during the annual “Tomatina” (tomato fight) festival in Bunol near Valencia, Spain, August 31, 2016. (Photo by Heino Kalis/Reuters)

A protester throws a stone towards a burning police bus in front of him, during clashes with police, in central Kiev, Ukraine, Sunday, January 19, 2014. Hundreds of protesters on Sunday clashed with riot police in the center of the Ukrainian capital, after the passage of harsh anti-protest legislation last week seen as part of attempts to quash anti-government demonstrations. The violent scenes further escalated this ex-Soviet republic's political crisis and showed a rift among opposition leaders, one of whom fought bravely to stop the violence, while others condemned the events from afar. (Photo by Evgeny Feldman/AP Photo)

Matt Town of the st Centingas historic re-enactment group poses for portraits in his home while wearing his replica Saxon armour on October 12, 2016 in Ramsgate, England. This weekend marks the 950th anniversary of 1066, the Battle of Hastings and the Norman Conquest, and many historical groups will be participating in a large-scale re-enactment on the site of the original battle. (Photo by Leon Neal/Getty Images)

Festive characters perform during Harrods 26th Annual Christmas Parade on November 5, in London, England. (Photo by Steve Finn/Harrods via Getty Images)