Over 30 Douglas C-47 Skytrains (Dakotas) making final preparations for flight formation practice before the 75th D-Day Anniversary flight to Normandy in Duxford, England on June 4, 2019. (Photo by UK Air Force Images)

Yan Mengjie sits on a boat as she poses for photos near Erhai Lake in Dali Bai Autonomous Prefecture, Yunnan province, China on June 16, 2019. Erhai is one of China's biggest freshwater lakes and a backdrop to the city of Dali, which drew 47 million visitors last year, more than triple the number in 2010. Hotels and homestays have sprung up along a 31-mile (50-km) stretch of lakeside road to accommodate tourists. But officials ordered some hotels demolished after President Xi Jinping during a 2015 visit called for the lake to be protected. (Photo by Tingshu Wang/Reuters)

The band “Baby In Vain” and the dancegroup Corpus perform at the Gloria Stage at Roskilde Festival on July 3, 2019. (Photo by Helle Arensbak/Ritzau Scanpix/AFP Photo)

A robin perches on a spade handle in a garden on a rainy day in Lixwm, north Wales. Researchers said this week that when European robins are subjected to human-produced noise, their behaviour changes. (Photo by DGDImages/Alamy Live News)

A Saudi police officer receives emergency calls at a call center, ahead of the Hajj pilgrimage in the Muslim holy city of Mecca, Saudi Arabia, Tuesday, August 6, 2019. The hajj occurs once a year during the Islamic lunar month of Dhul-Hijja, the 12th and final month of the Islamic calendar year. (Photo by Amr Nabil/AP Photo)

Syrian boys play with plastic guns on the first day of the Muslim religious festival of Eid al-Adha in al-Dana in Syria's rebel-controlled Idlib region, near the border with Turkey, on August 11, 2019. Muslims across the world are celebrating the first day of the Feast of Sacrifice, which marks the end of the hajj pilgrimage to Mecca and commemorates prophet Abraham's sacrifice of a lamb after God spared Ishmael, his son. (Photo by Aaref Watad/AFP Photo)

A life-size replica of a Diplodocus dinosaur watches people coming out of the subway in the city center of Bochum, Germany, Monday, August 12, 2019. The exhibition, featuring models of 33 dinosaurs all around the city center, is in Bochum due to the discovery of an 316 million years old dinosaur track found in a stone pit in the city six years ago. (Photo by Martin Meissner/AP Photo)

A family tries to cross a flooded road amid gushing water in Kolkata, India on August 17, 2019. Heavy rain continues for a second day in Kolkata, which contuinued to flood many streets all around the city. Authorities are working overtime to clear the roads. (Photo by Debarchan Chatterjee/Zuma Wire/Rex Features/Shutterstock)