Visitors walk past "Sculpture #1" by Darren Bader at the Frieze Art Fair in London, Britain October 14, 2015. The Frieze Art Fair, which is one of the world's leading contemporary art fairs, opens today and runs through October 17. (Photo by Suzanne Plunkett/Reuters)

A man walks past an advertisement sign promoting a bank in Seoul in this September 3, 2009 file photo. South Korea is expected to release GDP dara this week. (Photo by Lee Jae-Won/Reuters)

A worker refreshes himself with a fan after loading a container with rice bags at an export plant in the central Chainat province in Thailand, December 16, 2015. (Photo by Jorge Silva/Reuters)

A competitor reacts as she takes part in the “Tough Guy” adventure race near Wolverhampton, central England, on January 29, 2017. The Tough Guy event, which is being held for the final time in its 30th year, challenges thousands of competitors to run a gruelling course whilst negotiating over 200 obstacles including: water, fire, and tunnels. (Photo by Oli Scarff/AFP Photo)

A mahout walks with an elephant after bathing him in a river, before taking part in an elephant festival, which organisers say aims to raise awareness about elephants, in Sayaboury province, Laos February 17, 2017. (Photo by Phoonsab Thevongsa/Reuters)

Opposition students march against Venezuelan President Nicolas Maduro's government in Caracas February 12, 2015. Venezuelan troops blocked students during marches against Maduro on Thursday as pro-government supporters also rallied on the anniversary of 2014 protests that led to 43 deaths. In Caracas, troops cordoned off scores of students on an unauthorized march to a church where they planned a mass in honour of demonstrators who died. (Photo by Jorge Silva/Reuters)

A woman (L) places flowers at a grave next to a mummified body during exhumation works at the General Cemetery in Guatemala City, April 15, 2015. If a lease on a grave has expired or not been paid, grave cleaners will break open the crypts to remove and rebury the bodies. Any remains that have not been claimed are packed into plastic bags, labeled and stored in mass graves. Bodies that have been stored in the upper crypt are exposed to dry and sunny conditions which means they do not decompose and instead become mummified. (Photo by Jorge Dan Lopez/Reuters)

This aerial picture taken on June 6, 2016, shows the scene of a collision between a freight train and a passengers train on their way between Liege and Namur, in Saint-Georges-sur-Meuse, Eastern Belgium. Investigators worked through the wreckage of a high speed train crash in eastern Belgium on Monday that killed at least three people and injured nine others. A fast-moving passenger train late Sunday slammed violently into the back of a slow-moving freight train that was travelling on the same track for reasons that remain unexplained. (Photo by Laurie Dieffembacq/AFP Photo)