Festival crowd enjoying the weather on Day 1 of Reading Festival on August 25, 2017 in Reading, England. (Photo by Dean Fardell/Barcroft Images)

Giving out with a yell, Elke Sommer is tossed on the trampoline as she trains for her movie role as an athlete, on the playing field of the University of California at Los Angeles, June 8, 1967. (Photo by AP Photo)

Elvis Presley impersonator Sean Wright poses next to the Elvis Express train at Sydney's Central station before it departs for the 26th annual Elvis Festival being held in the New South Wales town of Parkes in Australia, January 11, 2018. (Photo by Daniel Munoz/Reuters)

Women dancing at the disco club Xenon in New York City, USA in 1978. Xenon was a popular disco in Manhattan in the late 1970s and early 1980s. It was the only nightclub popular enough to compete with Studio 54. (Photo by Waring Abbott/Getty Images)

Members of the Mayossa folk dance group pour water on a young woman in Kiskunmajsa, Hungary on April 2, 2018. According to an old Hungarian tradition, celebrated for several hundred years, young men pour water on young women, who in exchange present their sprinklers with beautifully colored eggs on Easter Monday. (Photo by Sandor Ujvari/EPA/EFE/Rex Features/Shutterstock)

New program of Munich's Krone Circus performed by two American artists “The Carmenas” during a press conference in Munich, Germany on January 10, 1962, while sitting in a coffee-house. (Photo by Heinrich Sanden Sr./AP Photo)

The National Geographic Photo Ark is a travelling exhibition of photographer Joel Sartore’s quest to create a photo archive of biodiversity around the world. So far, Sartore has captured studio portraits of more than 6,000 species – a number that he hopes to double. On 1 July, the ark will open at Melbourne zoo – the first time it has been exhibited in the southern hemisphere. More than 50 portraits will be on display, including many of Australian endangered animals being protected by programs at the zoo itself. These captions have been edited from text supplied by Melbourne zoo. Here: Barking owl. (Photo by Joel Sartore/National Geographic Photo Ark/The Guardian)

Sunrise over a moor viewed from Littaford Tor, Dartmoor, UK, 2016. Autumn visits the windswept moors and granite tors of Dartmoor earlier than the rest of the south-west. While there aren’t many trees here, autumn shades appear in golden ferns and tan heather. Littaford Tors, near Two Bridges and a mile from Princetown, is a short walk and can be combined with a visit to the adjacent Wistman’s Wood. (Photo by Stuart Holmes)