Ukrainian refugees embark on a ferry to cross the Danube river at the Ukrainian-Romanian border at Isaccea-Orlivka on March 25, 2022. - More than 3.6 million refugees have fled Ukraine since the Russian invasion, with more than two million of them heading to neighbouring Poland, according to the United Nations. A total of 10 million are believed to have fled their homes, according to the world body, representing over a quarter of the population in regions under government control. (Photo by Daniel MIHAILESCU / AFP)