Girls practice sit-ups during gymnastics lessons at the Shanghai Yangpu Youth Amateur Athletic School in Shanghai, China, on May 4, 2016. China's sports system has been enormously successful since the country returned to the Olympic fold in 1980, culminating with the host nation topping the medals' table at the 2008 Beijing Olympics. And yet, with the Rio de Janeiro Games less than three months away, the system is beginning to break down due to the shifting demographics of a more prosperous nation. (Photo by Aly Song/Reuters)

Soldiers from Japan's Ground Self Defense Force come ashore in amphibious assault vehicle as they train alongside U.S. Marines during the bilateral annual Iron Fist military training exercise in Camp Pendleton, California February 26, 2016. (Photo by Mike Blake/Reuters)

Londoners sleep on the platform and on the train tracks at Aldwych Underground station,London, during heavy all night Nazi bombing raids, October 8, 1940. (Photo by AP Photo)

Oded Balilty is an Israeli documentary photographer. He is an Associated Press photographer and won the Pulitzer Prize for Breaking News Photography in 2007. Photo: A Jewish settler struggles with an Israeli security officer during clashes that erupted as authorities evacuated the West Bank settlement outpost of Amona, east of the Palestinian town of Ramallah, in this February 1, 2006, file photo. (Photo by Oded Balilty/AP Photo)

Photo taken on October 11, 2020 shows a golden monkey at Dalongtan Golden Monkey Research Center in Shennongjia National Park of central China's Hubei Province. With the efforts of local authority and improvement of the environment in the past many years, the number of golden monkeys in Shennongjia area reached nearly 1,500 nowadays. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

A man stacks more bricks on his head while working at in brickfields Narayanganj near Dhaka, Bangladesh on January 02, 2021. (Photo by Kazi Salahuddin Razu/NurPhoto via Getty Images)

Elizabeth Svensson (right), 35 and Klaudia Zakrzewska, 27, from London, arrive back in the UK at Heathrow Terminal 2, after being on holiday in Dubai for 15 days, during England's third national lockdown to curb the spread of coronavirus on Friday January 29, 2021. (Photo by Yui Mok/PA Images via Getty Images)

This photo taken on December 2, 2015 shows a lenticular cloud forming as white streaks from airplanes mark the blue sky, in a rare atmospheric phenomena above the town of Gevgelija on December 2, 2015. Lenticular clouds have been regularly confused for UFOs throughout history due to the their smooth, round or oval lens-shaped structure. (Photo by Armend Nimani/AFP Photo)