A teacher gives an online lecture via webcam in an empty classroom at Algebra High School in Zagreb, Croatia, on March 18, 2020. Croatia announced on Thursday that a man who died a day ago had coronavirus, which made him the country's first coronavirus-related death. There are 102 confirmed cases of COVID-19 infection in the southeastern European country as of Thursday morning. (Photo by Borna Filic/Xinhua)

A teacher gives an online lecture via webcam in an empty classroom at Algebra High School in Zagreb, Croatia, on March 18, 2020. Croatia announced on Thursday that a man who died a day ago had coronavirus, which made him the country's first coronavirus-related death. There are 102 confirmed cases of COVID-19 infection in the southeastern European country as of Thursday morning. (Photo by Borna Filic/Xinhua)