A participant of the sled dogs race in action with the dogs in Stroehen (Lower Saxony), Germany, 18 October 2015. It is the first round of the North German Championship. (Photo by Peter Steffen/EPA)

Manuela (L) and Marta, members of the Revolutionary Armed Forces of Colombia (FARC), pose for a picture at a camp in the Colombian mountains on February 18, 2016. Many of these women are willing to be reunited with the children they gave birth and then left under protection of relatives or farmers, whenever the peace agreement will put an end to the country's internal conflict. (Photo by Luis Acosta/AFP Photo)

A PETA (People for the Ethical Treatment of Animals) activist with her body painted promotes veganism in Bangkok April 21, 2016. (Photo by Jorge Silva/Reuters)

2017 Paraguay-Bolivia-Argentina Dakar rally, 39th Dakar Edition, Seventh stage from Oruro to Uyuni, Bolivia on January 9, 2017. Juan Salvatierra of Bolivia rides his KTM. (Photo by Ricardo Moraes/Reuters)

Riot police stand guard behind a fire as refinery workers hold a blockade of the oil depot of Douchy-Les-Mines to protest against the government's proposed labour reforms, on May 25, 2016. Refinery workers stepped up strikes that threaten to paralyse France weeks ahead of the Euro 2016 tournament as the government moved to break their blockades, escalating a three-month tug-of-war over labour reforms. (Photo by François L.O./AFP Photo)

A couple embrace during the start of the San Fermin festival in Pamplona, Spain July 6, 2016. Revelers from around the world kick off the festival with a messy party in the Pamplona town square, one day before the first of eight days of the running of the bulls. (Photo by Vincent West/Reuters)

Two models sit in an acrylic “ZF-Car” from the German manufacturer of the same name at the Automechanika automotive service industry trade fair in Frankfurt am Main, Germany, 12 September 2016. The Automechanika Fair runs from 13 to 17 September 2016. (Photo by Boris Rössler/EPA)

An artist's impression of a growing supermassive black hole located in the early Universe is seen in this NASA handout illustration released on June 15, 2011. Using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe. This discovery from NASA's Chandra X-Ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies. (Photo by Reuters/NASA/Chandra X-Ray Observatory/A.Hobart)