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)

Mother and daughter volunteers Niki, right, and Rachel practice their pancake tossing technique in the streets of Wimborne model town and gardens before taking part in the Wimborne Minster virtual pancake race, in Wimborne, England, Tuesday February 16, 2021. Although a physical race cannot take place this year due to the coronavirus restrictions, Wimborne Minster has invited people to film themselves tossing a pancake for 30 seconds and posting it to Facebook. (Photo by Andrew Matthews/PA Wire via AP Photo)

People wait for Pope Francis to celebrate mass at the Franso Hariri Stadium in Irbil, Kurdistan Region of Iraq, Sunday, March 7, 2021. The Vatican and the pope have frequently insisted on the need to preserve Iraq's ancient Christian communities and create the security, economic and social conditions for those who have left to return (Photo by Andrew Medichini/AP Photo)

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)

A worker wearing a protective face mask, cleans up the road in front of a mural in Jakarta, Indonesia, 24 July 2020. Indonesian government has assigned a new team to rebuild the national economy amid the coronavirus pandemic. The country has started to ease COVID-19 lock-down restrictions in an effort to restart the economies and help people in their daily routines after the outbreak of coronavirus pandemic. (Photo by Mast Irham/EPA/EFE)

A man stands at a passenger train damaged in a collision with a freight train in Moscow region May 20, 2014. The passenger train on its way to Moldova collided with a freight train near Moscow on Tuesday, killing at least four people and injuring 15, a spokeswoman for Russia's Emergencies Ministry said. The reason for the collision, near the town of Naro-Fominsk 55 km (34 miles) southwest of Moscow, was not immediately clear. (Photo by Grigory Dukor/Reuters)

Students receive a group punishment during a military-style close-order drill class at the Qide Education Center in Beijing February 19, 2014. The Qide Education Center is a military-style boot camp which offers treatment for internet addiction. As growing numbers of young people in China immerse themselves in the cyber world, spending hours playing games online, worried parents are increasingly turning to boot camps to crush addiction. Military-style boot camps, designed to wean young people off their addiction to the internet, number as many as 250 in China alone. (Photo by Kim Kyung-Hoon/Reuters)

This picture taken on July 15, 2014 shows a bridge submerged in floodwaters in the ancient town of Fenghuang, central China's Hunan province. Rainstorms lashed central China's Hunan Province and southwest China's Guizhou Province, affecting over 1 million people and flooding a historical town, state media reported. (Photo by AFP Photo)