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)

Chinese soldiers leave after Chinese President Xi Jinping inspected troops of People's Liberation Army (PLA) Hong Kong Garrison at the Shek Kong Barracks in Hong Kong, Friday, June 30, 2017. Xi landed in Hong Kong Thursday to mark the 20th anniversary of Beijing taking control of the former British colony, accompanied by a formidable layer of security as authorities showed little patience for pro-democracy protests. (Photo by Kin Cheung/AP Photo)

A herd of elephants cross a road that passes through the flooded Kaziranga National Park in the northeastern state of Assam, India, July 12, 2017. (Photo by Anuwar Hazarika/Reuters)

“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)

Dancers perform inside of transparent balls during the Botanical Night at Botanical Garden in Berlin, Germany, 20 July 2018. During the Botanical Night a 16 kilometre long path along the flower beds and several themed gardens are illuminated and guide to many attractions. (Photo by Hayoung Jeon/EPA/EFE)

Revellers take part in the Notting Hill Carnival in London, Britain on August 27, 2018. The carnival has been held every year since 1966 and one of the largest festival celebrations of its kind in Europe. (Photo by Henry Nicholls/Reuters)

A ballet dancer practices in the sunshine at the Southbank skatepark in London on Monday, September 17, 2018, as Storm Helene is due to bring unseasonably warm weather in London and the south east, as the low pressure draws up warm air from the south. Forecasters have downgraded warnings that Helene could pose a risk to life when it hits this week – but warned coastal communities to stay vigilant. (Photo by Kirsty O'Connor/PA Wire)

A father crosses a road with his twin daughters in Shanghai, China September 28, 2018. (Photo by Aly Song/Reuters)