Sofia had hesitated to go back to her school in southern Ukraine, afraid that "something might happen because of the war."

Like hundreds of thousands of other children in her country, she has been learning remotely for years, first due to the coronavirus pandemic and then the risk of aerial attacks since Russia's invasion.

But after spending a few hours in her new classrooms, seven meters underground in a brightly lit anti-radiation bunker, the 12-year-old felt reassured.