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)

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)

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)

Gunfire erupted at a Denver pot celebration Saturday, injuring two people and scattering a crowd of thousands who had gathered for the first 4/20 counterculture holiday since the state legalized marijuana... Photo: A woman smokes a large marijuana joint at the Vancouver Art Gallery during the annual 4/20 day, which promotes the use of marijuana, in Vancouver, British Columbia April 20, 2013. (Photo by Ben Nelms/Reuters)

Zookeepers measure the length of a pueblan milk snake in the Reptile House of ZSL London Zoo as part of their annual weighing and measuring of their animals on August 25, 2011 in London, England. The heights and weights of over 750 different animal species at the zoo are recorded into the International Species Information System, to monitor their health and share the data with other zoos across the world. (Photo by Oli Scarff/Getty Images)

“Festive preparation”. Baghnapara, Bardhaman, West Bengal, India. Two girls prepare for the Gajan festival. They will perform a play based on Indian mythology. (Photo by Krishnasis Ghosh)

Devotees in a state of trance mimic creatures tattooed on their bodies during the annual Magic Tattoo Festival at Wat Bang Phra in Nakhon Pathom province, on the outskirts of Bangkok, Thailand March 19, 2016. Believers from across Thailand travel to the monastery to have their bodies adorned with tattoos and to pay their respects to the temple's master tattooist. They believe the tattoos have mystical powers, ward off bad luck and protect them from harm. (Photo by Chaiwat Subprasom/Reuters)