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)

Senator Barack Obama (D-IL) (R) stands in front of Senator Hillary Clinton (D-NY) as they arrive for U.S. President George W. Bush's annual State of the Union speech to a joint session of Congress at the U.S. Capitol in Washington in this January 23, 2007 file photo. Hillary Clinton announced her second run for the presidency on April 12, 2015 starting her campaign as the Democrats' best hope of fending off a crowded field of lesser-known Republican rivals and retaining the White House. (Photo by Larry Downing/Reuters)

A humanoid robot named Kansei, meaning “sensibility” in Japanese, makes a facial expression depicting “happiness”, next to the word “Love” during a demonstration at a laboratory of Meiji University's Robot and Science Institute in Kawasaki, south of Tokyo in this June 4, 2007 file photo. Three-fourths of robot installations over the next decade are expected to be concentrated in four areas: transportation equipment, including the automotive sector; computer and electronic products; electrical equipment and machinery. Labor costs have climbed in countries such as China that have been popular for outsourcing production, while technological advances for robots allow them to be more flexible and perform more tasks. (Photo by Yuriko Nakao/Reuters)

Arsenal football supporters cheering from the train carriage window as they leave Euston Station, London, on their way to Birmingham for their team's match against Aston Villa which they lost 3-5. (Photo by Douglas Miller/Topical Press Agency/Getty Images). 19th November 1932

Russian Orthodox believers take a dip in the ice cold water of a pond during the celebrations of the Orthodox Epiphany holiday, in Moscow, Russia on January 18, 2024. People believe that dipping into blessed waters during the holiday of Epiphany strengthens their spirit and body. (Photo by Yuri Kochetkov/EPA/EFE)

This picture taken on July 25, 2014 shows people cooling off in a waterpark in Suining, southwest China's Sichuan province. Meteorological departments issued an orange alert for high temperature as a heat wave embraces Sichuan province, with temperature of most area topped 37, local media reported. (Photo by AFP Photo)

U.S. Corporal Stanley Suski, left, and Miss Tamako, a Geisha girl, whirl a bit of Jitterbug, in a bar, in Tokyo, Japan, on October 1, 1945. (Photo by AP Photo)

Waura Indians wrestle during this year's “quarup”, a ritual held over several days to honour in death a person of great importance to them, in Xingu National Park, Mato Grosso State, Brazil August 25, 2013. (Photo by Ueslei Marcelino/Reuters)