A man walks on the road between Nouahibou and Nouakchott, where three Spanish aid workers were abducted in Mauritania, December 3, 2009. (Photo by Rafael Marchante/Reuters)

The Aurora Borealis (Northern Lights) lights up the sky near the village of Pallas (Muonio region) of Lapland, Finland September 8, 2017. (Photo by Alexander Kuznetsov/Reuters/All About Lapland)

Labourers pour molten iron into a container at a foundry in Xiangfan, Hubei province in this July 2, 2010 file photo. Iron ore is enjoying its biggest rally in years, outpacing copper and oil so far in 2016, but still weak forward prices show it may be tough to stretch the bullish outlook. Improving steel prices in top market China are helping fuel iron ore's climb as producers gear up for a seasonal uptick in demand. Yet there is no shortage of doubters who see gains in the bulk commodity as fleeting given a large glut and challenges for China's economy. (Photo by Reuters/Stringer)

Cheng Liping, whose husband Ju was onboard Malaysia Airlines Flight MH370 which disappeared on March 8, 2014, shows a picture of she and her husband together and an old card with a message given by her husband, at a park near her house where she and her husband used to visit during an interview with Reuters in Beijing July 24, 2014. Cheng said her life has been totally changed since the incident. Their two little sons, who don't know about this incident, keep asking her when their dad is coming back. Six months after Malaysia Airlines Flight MH370, with 239 mostly Chinese people on board, disappeared about an hour into a routine journey from Kuala Lumpur to Beijing March 8, loved ones of missing passengers derive what comfort they can from what's left behind after the world's greatest aviation mystery. More than two dozen countries have been involved in the air, sea and underwater search for the Boeing 777 but months of sorties failed to turn up any trace – even after narrowing the search area to the southern Indian Ocean – long after batteries on the black box voice and data recorders had gone flat. (Photo by Kim Kyung-Hoon/Reuters)

A man performs a split as he practices Kung Fu at Beihai Park in Beijing, China August 20, 2017. (Photo by Reuters/China Stringer Network)

Revellers pose during the 24th Street Parade dance music event in Zurich, August 29, 2015. (Photo by Arnd Wiegmann/Reuters)

Bar girls use their mobile phones outside a bar along the Walking Street where bars and sеx scenes are a commonplace July 31, 2016 in Pattaya, Thailand. Thailand's first female minister of tourism would like the sеx trade that is a huge business in the country to be banned. Tourists flock to Thailand for many sights including beautiful beaches but also for sеx tourism. Cities like Bangkok and Pattaya are well known as hubs of the Southeast Asian sеx trade, despite the fact that prostitution has been illegal in Thailand since 1960. (Photo by Paula Bronstein/Getty Images)

Laborers work on scaffolding near a full-scale replica of the Sphinx at an unfinished movie and animation tourism theme park, in Chuzhou, Anhui province, March 27, 2015. (Photo by Reuters/China Daily)