Students exercise in body training at Bishan Vocational Education Center in Chongqing, southwest China, January 13, 2016. These students were trained to be stewardesses of the high-speed train. (Photo by Xie Jie/Xinhua)

Elderly people attend an aquatic exercise at a private pool in Bangkok, Thailand, April 28, 2016. Many Thai families look after elderly relatives at a cost that countrywide adds up to just under a third of household income. The number of families facing this issue will balloon as the population ages at a rate among the fastest in Southeast Asia. (Photo by Athit Perawongmetha/Reuters)

This undated handout picture made available on February 3, 2016 and provided by Russia's punk band Рussy Riot shows Рussy Riot frontwoman Nadezhda Tolokonnikova performing in the band's new music video titled “Chaika” in Moscow. Russian punk band Рussy Riot, which became a symbol of resistance for a church performance slamming President Vladimir Putin, released a new protest song on February 3 mocking a senior official for alleged corruption. Titled “Chaika”, the satirical song and accompanying video take aim at prosecutor general Yury Chaika, whose two sons have been accused of using their father's position to accrue large fortunes. (Photo by Andrey Noskov/AFP Photo/Russian Punk Band Рussy Riot)

Shoppers walk down stairs featuring a five-metre-high reproduction of Vincent van Gogh's signature painting “Sunflowers”, at the entrance to Ocean Terminal in Hong Kong July 15, 2013. A premium three-dimensional reproduction of works of Van Gogh, the RELIEVO collection, approved by the curators of the Van Gogh Museum in Amsterdam, is on display at a gallery inside Harbour City shopping mall attached to the terminal. (Photo by Bobby Yip/Reuters)

The Elf on the Shelf balloon floats down Sixth Avenue during the 88th Annual Macy's Thanksgiving Day Parade in New York November 27, 2014. (Photo by Andrew Kelly/Reuters)

A girl rides a donkey as another walks by at the Shawqaba camp for internally displaced people who were forced to leave their villages by the war in Yemen's northwestern province of Hajjah March 12, 2016. In northwest Yemen, one of the poorest countries in the Middle East, about 400 families uprooted by the war have been stuck in the Shawqaba camp in Hajjah province for the past year. Residents live in poorly built huts that protect them neither from summer heat nor winter cold in a camp that lacks the most basic services. (Photo by Abduljabbar Zeyad/Reuters)

A general view of dried-up rivers in the Pilbara region of Western Australia December 2, 2013. Western Australia's Pilbara region, which is the size of Spain, has the world's largest known deposits of iron ore and supplies nearly 45 percent of global trade in the mineral. (Photo by David Gray/Reuters)

Bob Steele, of Jefferson, Texas, positions his bears during The Great Bear Show at the Dubuque (Iowa) County Fair on July 25, 2012. (Photo by Jessica Reilly/Telegraph Herald)