A member of the Community Police of the FUSDEG (United Front for the Security and Development of the State of Guerrero) poses with a weapon during events to mark the first anniversary of the force's operations in Ocotito, January 23, 2015. Based on the traditional indigenous justice system, the Community Police is made up of volunteers from different communities of Guerrero, and was created in response to the spate of violence in several locations in the state. (Photo by Jorge Dan Lopez/Reuters)

A boy sitting with his family looks up at a traditional Chinelo costumed dancer during a celebration 40 days after the birth of Jesus, in Xochimilco on the outskirts of Mexico City, February 2, 2015. The tradition of the Chinelo dates back to colonial times and the outfits and masks, which are supposed to resemble the faces of the Europeans and always sport an uptilted beard, became more elaborate between the 1800s and 1900s to make fun of the upper social classes. (Photo by Edgard Garrido/Reuters)

Emergency services work at the scene of a bus accident on the Kingsway in central London February 2, 2015. A number 91 double-decker bus had its roof ripped off after hitting a tree, causing injury to passengers and passers-by, local media reported. (Photo by Peter Nicholls/Reuters)

A decorated elephant march at the Navam Perahera, a Buddhist pageant of elephants, dancers and drummers, in Colombo February 3, 2015. Over 50 elephants participated in the street parade for Gangaramaya temple's annual Perahera festival, along with a nightly procession of traditional dancers, fire twirlers and traditional musicians. (Photo by Dinuka Liyanawatte/Reuters)

Storm chaser Brad Mack from Buena Park California videotapes a rotating supercell storm west of Newcastle, Texas April 9, 2013. Many of the storms in Tornado Alley that were forecast to be severe this week were taken out by a cold front from Canada. Picture taken April 9, 2013. (Photo by Gene Blevins/Reuters)

A giant sinkhole in Guatemala City, on May 31, 2010. More than 94,000 were evacuated as the storm buried homes under mud, swept away a highway bridge near Guatemala City and opened up several sinkholes in the capital. (Photo by Casa Presidencial/Reuters via The Atlantic)

A British couple drink hot chocolate at Chillout cafe in Dubai May 12, 2013. Chillout, owned by UAE's Sharaf Group, is the first ice lounge in the Middle East, with temperatures set at –6 degrees Celsius (21 degrees Farenheit). The cafe, with its illuminated interiors, curtains, paintings and seating arrangements, is all made of carved ice and frozen sculptures. (Photo by Ahmed Jadallah/Reuters)

A robot is seen on Mount Etna, Italy on July 4, 2017. Mount Etna, in Sicily, is a test bed for the approximately three-foot high, four-wheeled machine ahead of a future mission to the moon. It is being conducted by the German Aerospace Centre, the agency which runs Germany's space programme. (Photo by Antonio Parrinello/Reuters)