In this May 2016 photo released by The Ocean Agency/XL Catlin Seaview Survey, a boat sails near a coral reef that has been bleached white by heat stress in the Maldives. oral reefs, unique underwater ecosystems that sustain a quarter of the world's marine species and half a billion people, are dying on an unprecedented scale. Scientists are racing to prevent a complete wipeout within decades. (Photo by The Ocean Agency/XL Catlin Seaview Survey via AP Photo)

An Iraqi military vehicle passes displaced Iraqi boys returning to their homes in West Mosul's Oreibi neighbourhood after government forces retook control of the area from the Islamic State (IS) group during the ongoing offensive against the jihadists on May 21, 2017. (Photo by Ahmad Al-Rubaye/AFP Photo)

A bus goes through a flooded street in Wuhan, Hubei province, China July 6, 2016. (Photo by Reuters/China Daily)

The six-months-old female koala cub holds on to the back of zoo keeper Lena at the zoo in Duisburg, Germany, 23 October 2015. The yet unnamed baby weighs 580 grams. (Photo by Roland Weihrauch/EPA)

Andrej Ciesielski dangels his legs off the side of a building overlooking Times Square, New York City. (Photo by Andrej Ciesielski/Caters News Agency)

Syrian fighters from the Turkish-backed National Liberation Front (NLF) fire a missile against regime positions on May 13, 2019 in the rebel-held northern part of Syria's Hama province. Clashes on the edge of a jihadist bastion in northwestern Syria have killed at least 42 fighters in 24 hours, a monitor said today, after regime bombardment on the region devastated health services. (Photo by Omar Haj Kadour/AFP Photo)

An Indian man, Kalpesh Modi, performs stunts with his motorcycle during the rehearsal for the forthcoming Lord Jagannath Rath Yatra, an annual Hindi festival, in Ahmedabad on June 23, 2019. The 142nd Lord Jagannath Rath Yatra festival in Ahmedabad is scheduled for July 4. (Photo by Sam Panthaky/AFP Photo)

The trees on the iconic local landmark are silhouetted against glorious sunrise colours on a misty morning near Colmers Hill in Dorset, England on May 1, 2019. (Photo by Celia McMahon/Alamy Live News)