Children line up for their national anthem in the school courtyard where a stray dog sits by on the first day back to school in Minas, Cuba's Havana province, Tuesday, Sept. 1, 2026. (AP Photo/Ramon Espinosa)

Yurima Izaguirre, left, shines her cell phone flashlight during a blackout as her children brush their teeth and get ready for their first day back to school in Minas, Cuba's Havana province, Tuesday, Sept. 1, 2026. (AP Photo/Ramon Espinosa)

The Barroso family travels by horse-drawn carriage as they head to school for their two daughters' first day back to classes in Minas, Cuba's Havana province, Tuesday, Sept. 1, 2026. (AP Photo/Ramon Espinosa)

Yurima Izaguirre uses a cell phone flashlight due to a blackout as she wakes her children up to get them ready for their first day of back to school in Minas, Cuba's Havana province, Tuesday, Sept. 1, 2026. (AP Photo/Ramon Espinosa)

Girls hug as they arrive to school for their first day back to classes in Minas, Cuba's Havana province, Tuesday, Sept. 1, 2026. (AP Photo/Ramon Espinosa)

School children enter an underground school on their first day back, in Kharkiv, Ukraine, Tuesday, Sept. 1, 2026. (AP Photo/Andrii Marienko)

School children enter an underground school on their first day back, in Kharkiv, Ukraine, Tuesday, Sept. 1, 2026. (AP Photo/Andrii Marienko)

Children play in an underground shelter during an air raid alarm during the traditional back to school celebrations in Kyiv, Tuesday, Sept. 1, 2026. (AP Photo/Francisco Seco)