Željava Air Base, situated on the border between Croatia and Bosnia and Herzegovina under Plješevica Mountain, near the city of Bihać, Bosnia, was the largest underground airport and military air base in the former Yugoslavia, and one of the largest in Europe. (Photo by Thomas Windisch/Exclusivepix Media)

A woman and a child make a bonfire at a makeshift camp for migrants and refugees at the Greek-Macedonian border near the village of Idomeni, Greece, April 1, 2016. (Photo by Marko Djurica/Reuters)

A girl attends a performance hosted by the Ministry of the Interior that includes police, border guards, and rescuers celebrating International Children's Day in Kyiv, Ukraine on June 1, 2021. (Photo by Gleb Garanich/Reuters)

Border Security Force (BSF) soldiers ride their camels as they take part in a rehearsal for a road show ahead of the visit of U.S. President Donald Trump, in Ahmedabad, India, February 21, 2020. (Photo by Amit Dave/Reuters)

Refugees and migrants try to find a place on an already full train headed for Serbia, near the city of Gevgelija, The Former Yugoslav Republic of Macedonia, on February 24, 2016. Refugees and migrants from Iraq and Syria continue to pass through Macedonia on their way to the European Union. (Photo by Georgi Licovski/EPA)

Anton Phung, known as B-Boy LB, and Karam Singh, or Kid Karam, show off their dancing skills in Salford on November 3, 2022 before the WDSF European Breaking Championships, which will be held in Manchester this weekend. (Photo by James Glossop/The Times)

Gold medalist Mujinga Kambundji, of Switzerland, left, and silver medalist Ewa Swoboda, of Poland, celebrate after finishing the Women 60 meters final at the European Athletics Indoor Championships at Atakoy Arena in Istanbul, Turkey, Friday, March 3, 2023. (Photo by AP Photo/Stringer)

Jazmin Sawyers of Great Britain competes in the Women's Long Jump Final during the Athletics competition on day 8 of the European Championships Munich 2022 at Olympiapark on August 18, 2022 in Munich, Germany. (Photo by Alexander Hassenstein/Getty Images)