Tao Xiangli gets out of his homemade submarine after operating it in a lake on the outskirts of Beijing September 3, 2009. Amateur inventor Tao, 34, made a fully functional submarine, which has a periscope, depth control tanks, electric motors, manometer, and two propellers, from old oil barrels and tools which he bought at a second-hand market. He took 2 years to invent and test the submarine which costs 30,000 yuan ($4,385). (Photo by Christina Hu/Reuters)

Passengers wait for a train to depart from the Hankou Railway Station in Wuhan, central China's Hubei province, Friday January 13, 2017. Officials expect that Chinese travelers will make almost 3 billion trips during the holiday travel rush that starts runs through Feb. 21. These trips include intercity flights, trains and local bus rides to villages for China's 1.4 billion people. (Photo by Chinatopix via AP Photo)

A performer practices her mermaid swim next to a shark in an aquarium after graduating from a mermaid workshop in Guangzhou, Guangdong Province, China December 16, 2016. (Photo by Tyrone Siu/Reuters)

Detainees look out from a prison cell at a compound of the Lukyanivska detention centre in Kiev, Ukraine, July 19, 2016. (Photo by Valentyn Ogirenko/Reuters)

Inmates dressed as Santa Claus prepare to participate in an event ahead of Christmas celebrations at Santa Monica female prison in Lima December 19, 2014. (Photo by Enrique Castro-Mendivil/Reuters)

A military guard observes from a watch tower at the Combinado del Este prison during a media tour in Havana, Cuba, Tuesday, April 9, 2013. Cuban authorities led foreign journalists through the maximum security prison, the largest in the Caribbean country that houses 3,000 prisoners. Cuba says they have 200 prisons across the country, including five that are maximum security. (Photo by Franklin Reyes/AP Photo)

A customer shops at an Alibaba rural service centre in Jinjia Village, Tonglu, Zhejiang province, China, July 20, 2015. E-commerce growth in the countryside now outpaces that in major cities, though fewer than one tenth of online purchases made on Alibaba platforms were shipped to rural areas in the first quarter of this year. Alibaba estimates the potential market at 460 billion yuan ($74 billion) by next year. (Photo by Aly Song/Reuters)

Members of the Shanxi Folk Dance and Music Troupe perform during a rehearsal before a show at the Orient Museum in Lisbon February 1, 2016. The show is part of the Chinese New Year Celebrations program of Orient Museum in Lisbon. (Photo by Rafael Marchante/Reuters)