A mother of a victim who was onboard sunken ferry Sewol, leaves a message on a desk used by her child at an empty classroom, which was preserved since the disaster, at Danwon high school during the second anniversary of the disaster in Ansan, South Korea, April 16, 2016. (Photo by Kim Hong-Ji/Reuters)

Fifth-grade students of the General Yermolov Cadet School get prepared before their first military tactical exercise on the ground, which includes radiation resistance classes, forest survival studies and other activities, in Stavropol, Russia, September 10, 2016. Picture taken September 10, 2016. (Photo by Eduard Korniyenko/Reuters)

These girls are all smiles as they celebrate surviving A-level results day in Birmingham, England on August 15, 2019. The A Level is a subject-based qualification conferred as part of the General Certificate of Education, as well as a school leaving qualification offered by the educational bodies in the United Kingdom. (Photo by SnapperSK/SnapperMS)

A girl yawns as she and others wait for the start of their first day in school, an occasion known as the Day of Knowledge, in the small town Ignalina, some 110km (68 miles) north of the capital Vilnius, Lithuania, Monday, September 2, 2019. (Photo by Mindaugas Kulbis/AP Photo)

Yeshiva School students briefly dance on Grant Street after the menorah lighting outside of the City-County Building for the fifth night of Hanukkah, Thursday, December 26, 2019, in downtown Pittsburgh. (Photo by Alexandra Wimley/Pittsburgh Post-Gazette via AP Photo)

Women Wrestlers, Bolivia. Lucha libre (Bolivian wrestling) is one of the most popular sports in the country. Women wrestlers are known as cholitas and have in the last ten years become popular in the sport. Here, Carmen Rosa and Yulia la Pacena perform in a benefit show to raise money for the bathrooms of a school in La Paz, Bolivia, 26 June 2011. (Photo by Daniele Tamagni)

Dolly the Chihuahua dog dressed as Alice in Wonderland is photographed during an Alice in Wonderland and Charlie and the Chocolate Factory themed Furbabies Dog Pageant at Jodhpurs Riding School in Tockwith, North Yorkshire, Sunday September 6, 2020. (Photo by Danny Lawson/PA Wire via AP Photo)

Grade 5 student Lovely Joy De Castro, 11, takes notes while attending an online class using a smartphone, as schools remain closed during the Coronavirus disease (COVID-19) outbreak, at Manila South Cemetery where she lives with her family in Makati City, Philippines, November 6, 2020. (Photo by Eloisa Lopez/Reuters)