School teachers and staff members take part during an active shooter training at James I. O'Neill High School in Highland Falls, New York, U.S., December 12, 2017. (Photo by Eduardo Munoz/Reuters)

A girl peeps at a gate as primary school students enter to attend an open air class near their school building as part of an initiative from the government following restrictions imposed to control the spread of the Covid-19 coronavirus, in Kolkata on February 7, 2022. (Photo by Dibyangshu Sarkar/AFP Photo)

In this February 19, 2014 photo, a skate seller puts slices of skate into styrofoam boxes for shipment to customers around South Korea at a fish market in Mokpo, a port city on the southwestern tip of the Korean Peninsula. The aroma of one of southwestern South Korea's most popular delicacies regularly gets compared to rotting garbage and filthy bathrooms. And that's by fans. The unusual dish is typically made by taking dozens of fresh skate, a cartilage-rich fish that looks like a stingray, stacking them up in a walk-in refrigerator and waiting. Up to a month in some cases. (Photo by Ahn Young-joon/AP Photo)

A large sand sculpture is seen at the site of Yokohama Sand Art Exhibition – Culture City of East Asia 2014 on July 16, 2014 in Yokohama, Japan. Producer and sand sculptor Katsuhiko Chaen invited artists from around the world including South Korea and China, to recreate the World Heritage and historical buildings in China, Japan and South Korea. The exhibition will be open from July 19 to November 3, 2014. (Photo by Chris McGrath/Getty Images)

South Korean rescue members wearing chemical protective suits walk past a monster character (R) during an anti-terror drill as part of a disaster management exercise at the COEX shopping and exhibition center in Seoul on May 20, 2016. South Korea is holding its 2016 Safe Korea anti-disaster exercise this week against terrorist threats and natural disasters. (Photo by Jung Yeon-Je/AFP Photo)

Girls during a class at the Teire Irish dance school in Moscow, Russia on March 15, 2019. (Photo by Sergei Karpukhin/TASS)

Russian cadets march during the annual cadet schools get-together in Moscow, Russia on March 30, 2018. (Photo by Mladen Antonov/AFP Photo)

A girl goes to school just before sunrise in Frankfurt, Germany, Wednesday, December 11, 2019. (Photo by Michael Probst/AP Photo)