The students meet a day a week for lessons in a tiny underground classroom that teachers call the beehive, for the buzzing of all the children packed inside.

Holding classes above ground in this part of Ukraine, in the city of Balakliya near the front line, is considered too dangerous because of the ever-present threat of Russian missiles and drones. Children spend most of their time in online classes and take turns going to school underground.

“When they come, they often ask me, ‘Can we see our former classroom?’” said Inna Mandryka, a deputy principal. The teachers, she said, never imagined children longing for school so much.

Russia’s invasion of Ukraine was intended to undermine the country’s future in many ways, stamping out language and culture, destroying infrastructure and leveling whole cities with bombs in the country’s east.

Disruption to the education of Ukraine’s 3.7 million schoolchildren is one of the most serious challenges for the country. Classes have been repeatedly interrupted, leaving many students far behind academically, experts say. Children are also losing their soft skills, such as communication and conflict resolution, from being unable to interact enough with other students.

Providing classes of any kind has been a huge obstacle for the country since Russia’s full-scale invasion began in 2022.