Photochromes are vibrant and nuanced prints hand-coloured from black-and-white negatives. Created using a process pioneered in the 1880s, these images offer a fascinating insight into the world when colour photography was still in its infancy. A Tour of the World in Photochromes is at the Swiss Camera Museum, Vevey, until 21 August. Here: Street food in the Strada del Porto in Naples, Italy, 1899. (Photo by Swiss Camera Museum/The Guardian)

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)

Men eat oranges from a push cart along a road as a vehicle travels past them in Karachi January 22, 2015. (Photo by Akhtar Soomro/Reuters)

Russia' s President Vladimir Putin (L) congratulates prizewinners at the 2018 Youth Judo Tournament dedicated to Soviet and Russian judo coach Anatoly Rakhlin, and held at St Petersburg' s Yubileyny Palace of Sports in St Petersburg, Russia on May 23, 2018. (Photo by Mikhail Metzel/TASS)

People mourn next to the body of Muddasir Khan, who was wounded on Tuesday in a clash between people demonstrating for and against a new citizenship law, after he succumbed to his injuries, in a riot affected area in New Delhi, February 27, 2020. (Photo by Adnan Abidi/Reuters)

Fabian Ramirez, 11, scavenges a trash container for vegetables with his family that were discarded at the “Mercado de Abasto”, a market for vendors, during the fourth week of a quarantine to help contain the spread of the new coronavirus in Asuncion, Paraguay, Thursday, April 2, 2020. (Photo by Jorge Saenz/AP Photo)

Riot police wear face masks, as a precautionary measure against the COVID-19 coronavirus, allow a women to cross a cordon after a protest by pro-democracy demonstrators at a shopping mall in Hong Kong on May 9, 2020. (Photo by Isaac Lawrence/AFP Photo)

A farmer carries a bundle of wheat after harvesting it from a field in the Gharbia Governorate, as Egypt ramps up efforts to slow the spread of the coronavirus disease (COVID-19), Egypt on May 14, 2020. (Photo by Mohamed Abd El Ghany/Reuters)