Women wearing bikinis and Santa Claus hats participate in a promotional event to celebrate the upcoming Christmas at a ski resort in Xuchang, Henan province, December 23, 2014. Ten women wore Santa Claus-themed bikinis to welcome the coming Christmas in temperatures below zero Celsius. (Photo by Reuters/Stringer)

Alex Plunkett, left, and Sean Hart, both of Arlington, Va., join hundreds participating in the annual International Pillow Fight Day on April 5. Massive pillow fights broke out on the Mall in Washington and in cities around the world. (Photo by Marvin Joseph/The Washington Post)

A Japanese girl participates in a calligraphy contest to the celebrate the New Year in Tokyo January 5, 2015. Over 3,000 calligraphers, having qualified in country wide competitions throughout Japan, took part in the annual contest to celebrate the new year. (Photo by Issei Kato/Reuters)

South Korea's Amry Special Warfare Command (SWC) soldiers aim their machine guns in a frozen river during a winter exercise in Pyeongchang, South Korea, Thursday, January 8, 2015. About 200 SWC soldiers participated in this routine two-week winter drill. (Photo by Ahn Young-joon/AP Photo)

Women wearing prosthetic legs participate in a public photo session at the Hasselblad and Profoto booth, during the CP+ camera and imaging equipment trade fair in Yokohama south of Tokyo, February 14, 2015. Japanese prosthetist Fumio Usui inspired the event after collaborating with photographer Takao Ochi in the book project “Amputee Venus” that portrays 11 Japanese women with artificial legs, local media reported. (Photo by Thomas Peter/Reuters)

A snowboarder performs during the Red Bull Jump and Freeze competition at ski resort Shimbulak outside Almaty March 22, 2015. Participants wearing festive costumes perform tricks before getting into a pond with icy water. (Photo by Shamil Zhumatov/Reuters)

A participant holds his dog as colored powder is thrown into the air during the Color Run in Lausanne, Switzerland, 12 September 2015. The international 5km running event is inspired by the Hindu Holi spring festival of colors. (Photo by Valentin Flauraud/EPA)

A participant tries to tie a steer during the Russian Rodeo in the village of Kotliakovo, Bryansk region, southeast of Moscow, Russia, September 12, 2015. The competition was organised by privately held Miratorg, one of the leading Russia's meat producers, between the divisions of the agricultural holding. (Photo by Maxim Shemetov/Reuters)