A man admires a sculpture in the series entitled 'Circle of Animals/Zodiac Heads' by Chinese artist Ai Weiwei in the courtyard of Somerset House on May 11, 2011 in London, England. The installation comprises of 12 bronze heads of animals which feature in the Chinese zodiac. The artist Ai Weiwei, who is outspoken in his criticism of the Chinese administration, was detained by authorities in Beijing on April 3, 2011 and his whereabouts remain unknown.

Japan's electronics equipment maker MuRata Manufacturing Co., Ltd's showcased their bicycle-riding robot “MuRata Boy” during the CEATEC Japan 2006 exhibition on October 3, 2006 in Chiba, Japan. The “MuRata Boy” robot can ride up a 25-degree slope, stop without losing its balance and make an S-curve without falling. (Photo by Koichi Kamoshida/Getty Images)

A visiitor bungee jumps during an outdoor festival to celebrate German Unity Day on the 21st anniversary of German reunification on October 3, 2011 in Berlin, Germany. German Unity Day is a national holiday and marks the day West Germany and East Germany were reunited in 1990 following the collapse of the Iron Curtain. (Photo by Adam Berry/Getty Images)

(L-R) Talents Yasmina Hunzinger, Lisa Martine Weller, Kim Sanders and Sharron Levy pose during a photocall to the TV show “The Voice of Germany” on January 3, 2012 in Berlin, Germany. (Photo by Andreas Rentz/Getty Images)

Young dancers perform at a preview show for the Chinese Lantern Festival which falls on February 6 and traditionally marks the end of the Lunar New Year celebrations on February 3, 2012 in Beijing, China.The Lantern Festival also known as the Yuanxiao Festival or Shangyuan Festival in China.(Photo by Lintao Zhang/Getty Images)

Spanish MotoGP rider Joan Mir (R) of Team Suzuki Ecstar and other MotoGP racers ride mini electric motorcycles at a fan event at Twin Ring Motegi in Motegi, Japan, 17 October 2019. The event was held ahead of the MotoGP race of Japan's Motorcycling Grand Prix scheduled for 20 October 2019. (Photo by Toru Hanai/EPA/EFE)

Frost covers part of the face of University of Minnesota student Daniel Dylla during a morning jog along Mississippi River Parkway Tuesday, January 29, 2019, in Minneapolis. Extreme cold and record-breaking temperatures are crawling into parts of the Midwest after a powerful snowstorm pounded the region, and forecasters warn that the frigid weather could be life-threatening. (Photo by David Joles/Star Tribune via AP Photo)

An Iraqi military vehicle passes displaced Iraqi boys returning to their homes in West Mosul's Oreibi neighbourhood after government forces retook control of the area from the Islamic State (IS) group during the ongoing offensive against the jihadists on May 21, 2017. (Photo by Ahmad Al-Rubaye/AFP Photo)