Aerial view of CRH bullet trains setting out ahead of Spring Festival travel rush on January 31, 2018 in Hefei, Anhui Province of China. About 2.98 billion trips will be made during the 40-day Spring Festival travel rush. China will take multiple measures to ensure a smooth Spring Festival travel rush. (Photo by VCG/VCG via Getty Images)

This picture shows a two-year old orangutan seized from a residents house at the provincial Nature Conservation and Agency (BKSDSA) office in Banda Aceh on September 16, 2014. The critically-endangered primates population are dwindling rapidly due to poaching and rapid destruction of their forest habitat that is being converted into palm oil plantations. (Photo by Chaideer Mahyuddin/AFP Photo)

A cadet lies on the grass after collapsing during a promotion ceremony at a police school in Bogota December 7, 2012. (Photo by John Vizcaino/Reuters)

A reveler, dressed as a Brazilian national army soldier holding a mock weapon with flowers jutting out of it, participates in the annual Gay Pride Parade in Sao Paulo, Brazil, Sunday, June 18, 2017. (Photo by Nelson Antoine/AP Photo)

Nigel Lamb from Great Britain, left, leading Juan Velarde of Spain, centre, and Martin Šonka of Czech Republic in the FAI Red Bull air race, Isle of Wight, UK on August 9, 2016. (Photo by Joerg Mitter/Red Bull/Global New/PA Wire)

Models backstage ahead of the St George New Generation show at Mercedes-Benz Fashion Week Australia 2015 at Carriageworks on April 16, 2015 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)

A participant runs towards the waters of the North Sea during the annual New Year's plunge event in Ostend, Belgium, January 2, 2016. (Photo by Francois Lenoir/Reuters)

A view of a stampede is seen during a New Year's celebration on the Bund, a waterfront area in central Shanghai, December 31, 2014. The stampede killed at least 35 people and injured 43 during New Year's Eve celebrations in Shanghai, on the city's famed waterfront tourist strip known as the Bund, authorities said. (Photo by Reuters/Stringer)