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)

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)

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)

“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)

Steampunk enthusiasts attend the sixth annual Haworth Steampunk Weekend in Haworth, northern England on November 25, 2018. The three-day alternative lifestyle festival features: music, dancers, entertainers, burlesque performers, vintage vehicles, a fashion show and a masquerade ball. Steampunk is a subgenre of science fiction or science fantasy that incorporates technology and aesthetic designs inspired by 19th-century industrial steam-powered machinery. (Photo by Oli Scarff/AFP Photo)

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

An Israeli soldier salutes as she attends a military cemetery ahead of the start of Remembrance Day at the graves of killed comrades on May 8, 2011 in Jerusalem, Israel. The 64th anniversary of the creation of Israel in 1948 has fallen on the Monday as determined by the Hebrew calendar and is preceded by the annual memorial recognising Israel's fallen soldiers. (Photo by Uriel Sinai/Getty Images)