A girl walks past campaign posters for long-time President Yoweri Museveni, as well as for local members of Parliament, on a street in Kampala, Uganda Wednesday, February 17, 2016. On the eve of presidential elections, a heavy police and military presence could be seen in the capital Kampala. (Photo by Ben Curtis/AP Photo)

A performer from the Academicos do Grande Rio samba school dances during carnival celebrations at the Sambadrome in Rio de Janeiro, Brazil, early Monday, February 16, 2015. (Photo by Silvia Izquierdo/AP Photo)

A member of “Laughter Doctors of Ciudad Juarez” performs at a children's hospital in Ciudad Juarez March 11, 2015. Through clown performances, music and interactive activities, the group of doctors visit different hospitals throughout the border city, using laughter to help aid the recovery of young and elderly patients suffering from serious illness or injury, as well as provide hope for the hospitalized patients and their families, local media reported. (Photo by Jose Luis Gonzalez/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)

A woman takes a selfie next to a model of Thor during the Middle East Film & Comic Con (MEFCC) in Dubai, United Arab Emirates, Saturday, April 11, 2015. (Photo by Kamran Jebreili/AP Photo)

People look at damaged trees after a tornado hit Funing on Thursday, in Yancheng, Jiangsu province, China June 24, 2016. (Photo by Aly Song/Reuters)

A girl carries a bag of recyclable items she collected from a landfill on the outskirts of Sanaa, Yemen November 16, 2016. (Photo by Mohamed al-Sayaghi/Reuters)

An employee operates a machine while attaching a lock to a silver chain at the jewelry department of the Krastsvetmet non-ferrous metals plant, one of the world's largest producers in the precious metals industry, in the Siberian city of Krasnoyarsk, Russia, December 14, 2016. (Photo by Ilya Naymushin/Reuters)