Revellers take part in an annual block party known as “Cordao de Prata Preta”, one of the many carnival parties to take place in the neighbourhoods of Rio de Janeiro, February 6, 2016. (Photo by Pilar Olivares/Reuters)

A handout image provided by the New Zealand Defence Force shows aid supplies being unloaded by Fijian soldiers from an Royal New Zealand Airforce C-130 Hercules plane in Suva, Fiji, 23 February 2016. Tool kits, generators, ration packs, water containers and chainsaws make up part of the New Zealand relief following Tropical Cyclone Winston. The death toll from the cyclone that hit Fiji over the weekend climbed to 29, local media reported ON 23 February. Cyclone Winston, the most powerful storm in Fiji's history, battered the country's main island of Viti Levu and other smaller surrounding islands on Saturday, the Fiji Broadcasting Corporation reported. (Photo by Sam Shepherd/EPA/NZ Defence Force)

Hotel staff practice self-defence skills after a training session given by team member of Special Weapons and Tactics (SWAT) team, in Hangzhou, Zhejiang province, April 7, 2016. (Photo by Reuters/Stringer)

Iranian Shiite Muslim women gather around a bonfire after rubbing mud on their body during the “Kharrah Mali” (Mud Rubbing) ritual to mark the Ashura religious ceremony in the city of Khorramabad, some 470 kms southwest of Tehran, early in the morning on October 1, 2017. “Khrreh Mali” or “Mud Rubbing” is a ritual that is held in the city of Khorramabad every year to commemorate the seventh century slaying of Prophet Mohammed' s grandson Imam Hussein, in which Iranian men roll over in mud and dry themselves by gathering around the bonfires before flagellating themselves. (Photo by Atta Kenare/AFP Photo)

Hospitality staff members laugh as they stand on Tiananmen Square before the closing ceremony of China's 19th Party Congress at the Great Hall of the People in Beijing, Tuesday, October 24, 2017. The ruling Communist Party on Tuesday formally lifted Xi Jinping's status to China's most powerful ruler in decades, setting the stage for the authoritarian leader to tighten his grip over the country while pursuing an increasingly muscular foreign policy and military expansion. (Photo by Mark Schiefelbein/AP Photo)

Vocalist Laila Skovmand, a musician with Danish company Between Music, plays underwater in a tank during a rehearsal ahead of their UK premiere concert Aquasonic at the Tramway in Glasgow on Ocrober 25, 2017. (Photo by Robert Perry/PA Images)

Faruk, 17, a Rohingya refugee trader holds betel leaves which are on sale at a stall in Palong Khali refugee camp near Cox's Bazar, Bangladesh, November 3, 2017. He left his village in Myanmar when the military opened fire towards the Rohingya. “I buy this betel leaf from Palong Khali market, in one bundle there are 160 pieces, I buy it for 80 taka and I sell it for 100 taka (1 Bangladeshi Taka = 0.012 US Dollar). Bangladeshi's and I sell for the same rate in the camp. Outside in the local market it is 80 taka per bundle. My problem is that I don't have money so I can't buy anything to eat, I can't buy fish to eat”, he said. (Photo by Hannah McKay/Reuters)

Gremio fans celebrate after their team won the Copa Libertadores final match at the Arena do Gremio in Porto Alegre, Brazil on November 29, 2017. (Photo by Diego Vara/Reuters)