Italian Air Force's aerobatic demonstration team, the Frecce Tricolori leave colourful vapour trails as they fly over the Altare della Patria monument on Republic Day (Festa della Repubblica) in Rome, Italy, 02 Jun 2017. The anniversary marks the founding of the Italian Republic in 1946. (Photo by Massimo Percossi/EPA)

This picture taken with an underwater camera shows Japan' s Yumi Adachi competing in the Mixed Duet technical final during the synchronised swimming competition at the 2017 FINA World Championships in Budapest, on July 17, 2017. (Photo by Bernadett Szabo/Reuters)

Demonstrators perform a dance in front of riot policemen during a march called by students to request changes in the education system in Santiago, Chile September 5, 2017. (Photo by Ivan Alvarado/Reuters)

Hospitality staff members laugh as they stand on Tiananmen Square before the closing ceremony of China's 19th Party Congress at the Great Hall of the People in Beijing, Tuesday, October 24, 2017. The ruling Communist Party on Tuesday formally lifted Xi Jinping's status to China's most powerful ruler in decades, setting the stage for the authoritarian leader to tighten his grip over the country while pursuing an increasingly muscular foreign policy and military expansion. (Photo by Mark Schiefelbein/AP Photo)

Guanacos sit during a signing ceremony in Patagonia Park, Chile, January 29, 2018. Chilean President Michelle Bachelet signed decrees Monday creating vast new national parks using lands donated by U.S. conservation organization Tompkins Conservation in what is believed to be the largest private donation of land ever from a private entity to a country. (Photo by Esteban Felix/AP Photo)

A lioness drinks after being fed by senior keeper Glynn Hennessy at ZSL London Zoo on August 10, 2016 in London, England. Today marks World Lion Day which highlights the first global campaign to celebrate the importance and plight of lions worldwide. (Photo by Carl Court/Getty Images)

A student from “the cliff village” in Atule'er climbs newly-constructed steel ladders after school to go home for holidays, in Liangshan Sichuan province, China, November 19, 2016. The steel ladders which replaced the unsafe vine ladders shortened the time taken for the children to go home, from three hours to two. (Photo by Reuters/Stringer)

This photo take on December 16, 2016 shows macaques monkeys playing on a motorbike in the grounds of a temple in Jaipur in the Indian state of Rajasthan. (Photo by Dominique Faget/AFP Photo)