SpaceX’s Dragon spacecraft, March 6, 2014. SpaceX's Falcon 9 rocket and Dragon spacecraft launched from Launch Complex 40 at the Cape Canaveral Air Force Station, Florida, for their third official Commercial Resupply (CRS) mission to the orbiting lab on April 18, 2014. Dragon returned to Earth with a parachute-assisted splashdown off the coast of southern California on May 14, 2014. Dragon is the only operational spacecraft capable of returning a significant amount of supplies back to Earth, including experiments. (Photo by Ron Lin/SpaceX Photos)

In this May 4, 2014 photo, a miner holds an amalgam of mercury and gold he mined after working a 28-hour shift at an illegal gold mining process, in La Pampa, in Peru's Madre de Dios region. Thousands of artisanal gold miners sweat through the long shifts and endure, for a few grams of gold, the perils of collapsing earth, limb-crushing machinery and the toxic mercury used to bind gold flecks. (Photo by Rodrigo Abd/AP Photo)

Fighters from Germany take up position before competing in the Medieval Combat World Championship at Malbork Castle, northern Poland, April 30, 2015. Medieval combat is a full contact sport that revives the foot based tournament fighting of medieval Europe. Countries fight in refereed matches where the objective is to get the opposing team to the floor. There are also duels with polearms, swords and shields where the number of hits landed are scored. The fighters, both male and female, wear heavy armours and weapons, mostly replicas of authentic pieces, and fight following the knights code of conduct. According to organizers, 25 nations from 6 continents are taking part in the Championships, which started on April 30 and will go on until May 3. (Photo by Kacper Pempel/Reuters)

A mobile phone cover with a picture of Russian President Vladimir Putin and which reads “Mr President” is seen in this photo illustration taken a in hotel room in Kazan, Russia, July 30, 2015. He may be in charge of an economy in crisis, but if mobile phone covers and souvenir mugs are a barometer of popularity, Russian President Vladimir Putin need not fear for his political future. In fact, Moscow's annexation of Crimea from Ukraine last year has given the memorabilia makers even more material to glorify, sometimes wryly, a president whose image as a champion of Russian national interests in a hostile world is barely challenged in his own country. (Photo by Stefan Wermuth/Reuters)

Humboldt Penguins swim in their pool as a keeper looks on through a spherical window during the annual stocktake press preview at London Zoo in Regents Park in London Monday, January 4, 2016. A requirement of ZSL London Zoo's license, the annual audit takes keepers a week to complete and all of the information is shared with zoos around the world via the International Species Information System, where it's used to manage the worldwide breeding programmes for endangered animals. (Photo by Alastair Grant/AP Photo)

A Cambodian resident wearing a mask attends a ceremony at Pring Ka-Ek village on the outskirts of Phnom Penh, Cambodia, 09 June 2016. Villagers organized a ceremony to continue their local traditions by paying respect to the Neakta Pring Ka-Ek (Spirit house) to prevent them from diseases and to achieve abundant rice harvests and other agricultural yields. (Photo by Mak Remissa/EPA)

A cat with a “stegosaurus spine” design cut into its fur is seen next to a dog at a pet shop, in Tainan, Taiwan June 19, 2016. Lee Mei-chen, Taiwanese hairdresser turned pet groomer, shaves paw prints, lion faces and characters from Japanese brand Hello Kitty on to animal backs. The teddy bear design is one of the most complex in the furry repertoire. Photo by Tyrone Siu/Reuters)

Taiwanese and Chinese nationals suspected of telecom fraud are surrounded by China police SWAT team and Cambodia police as they were deported to China at the International Airport of Phnom Penh, June 24, 2016. Scores of Chinese police officers swarmed the tarmac at Phnom Penh International Airport on Friday as 39 suspects arrested for their involvement in an alleged telecom scam were herded onto a chartered plane bound for China – including 25 Taiwanese nationals, whose government unsuccessfully attempted to have them repatriated. (Photo by Samrang Pring/Reuters)