Polish border guard seen at the Grzechotki border crossing in Poland. Russia invaded Ukraine on 24 February 2022, triggering the largest military attack in Europe since World War II. Up to 10 million Ukrainians have fled their homes, either leaving the country or moving to safer areas within Ukraine. Some 3 million refugees are thought to have crossed the borders into neighbouring countries. (Photo by Mateusz Slodkowski / SOPA Images/Sipa USA)