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)

A member of the Tinstix of Dynamite aerobatics team flies in front of a wall of fire during the Australian International Airshow in Melbourne on March 5, 2017. The annual event sees 180,000 visitors over the 3-day public event held at the Avalon Airfield some 80kms south-west of Melbourne. (Photo by Mal Fairclough/AFP Photo)

People enjoying the races on a wet day at Chester Racecourse on May 12, 2017 in Chester, England. (Photo by Alan Crowhurst/Getty Images)

A South China Tiger cub meets public at Guangzhou Zoo on June 22, 2017 in Guangzhou, Guangdong Province of China. Guangzhou Zoo boasts of the successful breeding of South China Tiger cub after 15 years. (Photo by VCG/VCG via Getty Images)

In this March 2, 2018 photo, an Andean man rests with his llama while tourists take in the natural wonder of Rainbow Mountain in Pitumarca, Peru. Tourists gasp for breath as they climb for two hours to the 16,404-foot (5,000-meter) peak in the Peruvian Andes, but stunned by the magical beauty that unfurls before them. (Photo by Martin Mejia/AP Photo)

Yoga students take a class with Nigerian Dwarf goats held by the 'Hello Critter Goat Yoga' team at the Golden Road Pub in Los Angeles, California on May 7, 2018. The goat yoga fitness craze is sweeping the United States with classes now held in pubs, farms and halls across the country. (Photo by Mark Ralston/AFP Photo)

Prostitutes working on 10th Ave in New York, USA on June 29, 1997. (Photo by Jon Naso/NY Daily News Archive via Getty Images)

“The Queen” painted fibreglass by artist John Humphreys is displayed backdropped by other works which feature in this year's Summer Exhibition on it's 250th year at the Royal Academy of Arts in London, Tuesday, June 5, 2018. The Summer Exhibition has been held since 1769, with around 1300 works on display this year and most of them available for purchase. It runs from June 12 until August 19. (Photo by Matt Dunham/AP Photo)