Chinese paramilitary guards monitoring passengers as they head to their train to travel to their hometowns for the “Spring Festival” or Lunar New Year at Nantong Railway Station in Jiangsu province, near Shanghai Travellers taking part in the world' s largest annual human migration must be home by January 27 to usher in the new year on January 28. (Photo by AFP Photo/Stringer)

A woman travels on a train stopping at a subway station visited by foreign reporters in central Pyongyang, North Korea on April 14, 2017. (Photo by Damir Sagolj/Reuters)

Actors dressed as a “Yeti” attend a promotional event for Travel Channel's “Expedition Unknown: Hunt for the Yeti” in Manhattan, New York City, U.S., October 4, 2016. (Photo by Brendan McDermid/Reuters)

Migrant children play with leaves during Christmas Eve at a shelter, as they travel with their parents as part of a caravan with humanitarian visas to transit throughout the country, in Monterrey, Mexico on December 24, 2021. (Photo by Daniel Becerril/Reuters)

South Asian countries in terms of total contribution of travel and tourism to GDP. #6. Vietnam, Total GDP: USD 202.6 billion (2016). Contribution of Travel and Tourism to GDP: 9.1% . Here: A boat in the Thu Bon River, Hoi An, Vietnam. (Photo by Domingo Leiva/Getty Images)

LCR Honda IDEMITSU's Japanese rider Takaaki Nakagami crashes in the second MotoGP free practice session of the Portuguese Grand Prix at the Algarve International Circuit in Portimao, on April 16, 2021. (Photo by Patricia de Melo Moreira/AFP Photo)

Homeless people receive free food offered by the Telangana state governement during a 21-day government-imposed nationwide lockdown as a preventive measure against the COVID-19 coronavirus in Hyderabad on March 26, 2020. (Photo by Noah Seelam/AFP Photo)

Young children at a Bristol, Great Britain health centre unsure of the benefits of sun-lamps and the special glasses that must be worn, July 1948. The health centre was part of the newly introduced free National Health Service. (Photo by Popperfoto/Getty Images)