Secondary school students jump into the sea to celebrate the end of a school year in Zadar, Croatia, on May 25, 2021. The celebration of "Norijada" (Crazy Day) is held annually nationwide in Croatia to mark the end of a school year. (Dino Stanin/Pixsell via Xinhua)

Secondary school students celebrate the end of a school year in Zadar, Croatia, on May 25, 2021. The celebration of "Norijada" (Crazy Day) is held annually nationwide in Croatia to mark the end of a school year. (Dino Stanin/Pixsell via Xinhua)

A secondary school student is pushed into the sea to celebrate the end of a school year in Zadar, Croatia, on May 25, 2021. The celebration of "Norijada" (Crazy Day) is held annually nationwide in Croatia to mark the end of a school year. (Dino Stanin/Pixsell via Xinhua)

Secondary school students jump into the sea to celebrate the end of a school year in Zadar, Croatia, on May 25, 2021. The celebration of "Norijada" (Crazy Day) is held annually nationwide in Croatia to mark the end of a school year. (Dino Stanin/Pixsell via Xinhua)

Secondary school students jump into the sea to celebrate the end of a school year in Zadar, Croatia, on May 25, 2021. The celebration of "Norijada" (Crazy Day) is held annually nationwide in Croatia to mark the end of a school year. (Dino Stanin/Pixsell via Xinhua)