A U.S. Army soldier with the 10th Special Forces Group and his military working dog jump off the ramp of a CH-47 Chinook helicopter from the 160th Special Operations Aviation Regiment during water training over the Gulf of Mexico as part of exercise Emerald Warrior 2011 on March 1, 2011. (Photo by Tech. Sgt. Manuel J. Martinez/U.S. Air Force)

Military helicopters fly in formation above a billboard with a picture of China's late Chairman Mao Zedong during a training session for the upcoming parade marking the 70th anniversary of the end of World War Two, on the outskirts of Beijing, July 2, 2015. Troops from Russia and Mongolia will march together with Chinese forces in a parade in Beijing in September to commemorate the end of World War Two, the government and state media said on Thursday, confirming the first two foreign participants. (Photo by Jason Lee/Reuters)

Passengers hold 500 (bottom) rupee banknotes to buy train tickets at a railway booking counter in Allahabad, India, November 9, 2016. People are queuing up outside banks across India to exchange 500 and 1,000 rupee notes after they were withdrawn as part of anti-corruption measures. Indians will be able to exchange their old notes, which stopped being legal tender at midnight on Tuesday, for new ones at banks until 30 December. The surprise move is part of a government crackdown on corruption and illegal cash holdings. Banks were shut on Wednesday to allow them enough time to stock new notes. There are also limits on cash withdrawals from ATMs. The BBC's Yogita Limaye in Mumbai says there have been chaotic scenes outside many banks. (Photo by Danish Siddiqui/Reuters)

This picture taken on October 20, 2016 shows students practising wushu at the Tagou martial arts school in Dengfeng. China is investing hugely in football training and has vowed to have 50 million school- age players by 2020, as the ruling Communist party eyes “football superpower” status by 2050. (Photo by Nicolas Asfouri/AFP Photo)

A member of the “Sibspas” Siberian search and rescue group dressed as Santa Claus (R), waits for his team mate, dressed as Father Frost, the Russian equivalent of Santa Claus, as he climbs the rock named “The Fourth Stolb” (the Fourth Pillar) at the Stolby national nature reserve during a training session of the Russian Emergencies Ministry, outside the Siberian city of Krasnoyarsk, Russia December 15, 2015. (Photo by Ilya Naymushin/Reuters)

A vendor (C) serves customers at a vegetable market as a commuter train passes in Jakarta October 2, 2015. Indonesia's high annual inflation rate cooled in September and should drop more by year-end, but it likely will be 2016 before the central bank can cut interest rates to help an economy growing at its slowest pace in six years. (Photo by Reuters/Beawiharta)

This aerial photo shows bullet trains parked at a station in preparation for the upcoming Lunar New Year travel peak in Nanjing, in eastern China's Jiangsu province on January 27, 2021, as authorities have encouraged people to stay put during the Spring Festival to curb the spread of of COVID-19 coronavirus. (Photo by AFP Photo/China Stringer Network)

Omar Gamal, a 28-year-old pigeon keeper, stands next to his pigeon coop on his rooftop in the Egyptian capital's twin city of Giza on February 21, 2021, with the Pyramids of (R to L) Khufu (Cheops), Khafre (Chephren), and Menkaure (Menkheres) in the background. An ancient tradition handed down through the generations, the practice of domesticating pigeons stretches across borders from the banks of the Nile to north Africa and beyond, with people not only training birds for competitions, but also serving them up as a dining delicacy. (Photo by Khaled Desouki/AFP Photo)