Lightning illuminates a thundercloud as a storm front hits the North Sea region near Westerhever, northern Germany, on August 11, 2014. (Photo by Daniel Reinhardt/AFP Photo/DPA)

Rick Sorenson, owner of the Rio Ramaza Marina, wades in the Sacramento River after securing an old paddlewheel boat on his property as the river makes its way up the levee on Garden Highway in Sacramento, Calif., Monday, January 9, 2017. (Photo by Hector Amezcua/The Sacramento Bee via AP Photo)

A man carries his dog as he prays during Vesak Day, an annual celebration of Buddha's birth, enlightenment and death, at Wat Yai Chai Mongkhon temple in Ayutthaya, Thailand, May 10, 2017. (Photo by Athit Perawongmetha/Reuters)

A monkey leaps into a pond on a hot day in Allahabad on May 19, 2017. According to local reports temperatures have soared in the northern Indian city to 47.28 Celsius. (Photo by Sanjay Kanojia/AFP 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)

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)

Iraqi children play with a ball on a street blocked with burning tyres, amid a general strike in the southern city of Basra, on November 25, 2019. The demonstrations rocking the capital and Shiite-majority south since October 1 are the biggest grassroots movement the country has seen in decades. Sparked by outrage over rampant government corruption, poor services and lack of jobs, they have since gone straight to the source: calling out the ruling system as inherently flawed and in need of a total overhaul. (Photo by Hussein Faleh/AFP Photo)

Syrian dancer and choreographer Yara al-Hasbani performs a dance on the empty Trocadero square in front of the Eiffel tower in Paris on April 22, 2020, on the 37th day of a strict lockdown in France to stop the spread of COVID-19 (novel coronavirus). (Photo by Sameer Al-Doumy/AFP Photo)