People pass a suitcase as they line up to enter a railway station in Beijing, February 15, 2015. Chinese Ministry of Transport said a total of 2.807 billion trips are expected to be made during the 40-day Spring Festival travel rush, which started on February 4 and will last until March 16, Xinhua News Agency reported. (Photo by Reuters/Stringer)

A German Air Force Officer sits astride a dead boar outside a house where he is stationed near the Western Front, in this 1918 handout picture. This picture is part of a previously unpublished set of World War One (WWI) images from a private collection. The pictures offer an unusual view of varied and contrasting aspects of the conflict, from high tech artillery to mobile pigeon lofts, and from officers partying in their headquarters to the grim reality of life and death in the trenches. The year 2014 marks the centenary of the start of the war. (Photo by Reuters/Archive of Modern Conflict London)

Carlos Bahia, dressed as Santa Claus, talks with boys at the Maresias beach, in the state of Sao Paulo December 9, 2014. In the Southern Hemisphere summer starts on December 1, so while countries in the north are experiencing a white Christmas with grey skies, those in the south are busy surfing and sunbathing in temperatures just shy of 100 degrees Fahrenheit (38 degrees Celsius). (Photo by Nacho Doce/Reuters)

A Kurdish girl wears her relative's assault rifle and ammunition belt as she waits at the Iraqi Kurdish Shaqouli checkpoint, some 35 kilometres east of Mosul, on November 10, 2016. Since the start of the Mosul offensive the Kurds have moved their border some 10 kms closer to Iraq's second city, marking it out with a line in the sand. (Photo by Odd Andersen/AFP Photo)

Estonia's olympic team female marathon runners triplets (L-R) Lily, Liina and Leila Luik run during a training session in Tartu, Estonia, May 26, 2016. Leila, Liina and Lily Luik will make Olympics history as the first identical triplets to compete against each other when they cross the start line for the women's marathon in Rio. (Photo by Ints Kalnins/Reuters)

A tourist poses next to a tiger before officials start moving tigers from Thailand's controversial Tiger Temple, a popular tourist destination which has come under fire in recent years over the welfare of its big cats in Kanchanaburi province, west of Bangkok, Thailand, May 30, 2016. Wildlife authorities raid a Buddhist temple that has more than 100 tigers, taking away three cats and vowing to confiscate scores more in response to global pressure over wildlife trafficking. (Photo by Chaiwat Subprasom/Reuters)

A boy walks by a model of a dinosaur wearing a face mask, during a partial lockdown to prevent the spread of the coronavirus, at the Museum of Natural History in Brussels, Tuesday, May 19, 2020. Museums are hesitantly starting to reopen as the coronavirus lockdown measures are relaxed, yet experts say that one in eight in the world could potentially face permanent closure because of the pandemic. (Photo by Virginia Mayo/AP Photo)

A Sri Lankan man use a scarf as a protective mask as he waits for a swab test at a locked-down area in Colombo, Sri Lanka, 14 May 2020. The Sri Lankan government has started lifting most of the restrictions implemented nearly two months ago in a bid to slow down the spread of the SARS-CoV-2 coronavirus causing the COVID-19 disease and is preparing for a full reopening of businesses and a resumption of activities to avoid an economic slump. (Photo by Chamila Karunarathne/EPA/EFE/Rex Features/Shutterstock)