Jackson Sharman

Russian forces continue to force their way into Ukraine’s inner defenses, over four weeks (at time of writing) after the initial invasion. The Ukrainian military is mustering a spirited defense that has won sympathy from the rest of the world, though it is still uncertain when the war will end.

Ukrainians who have been forced to flee because of the Russian invasion have also drawn international support. As of March 31, the United Nations reports that over 4 million people—almost 10% of the Ukrainian population—have left the country since the start of the war. This is the largest number of refugees in Europe since the end of WWII. An additional 6.5 million people are estimated to be internally displaced in Ukraine.

The high commissioner of the United Nations’ refugee agency, Filippo Grandi, said: “I have worked in refugee crises for almost 40 years, and I have rarely seen such an incredibly fast-rising exodus of people.”

The refugees are mainly women, children, and the elderly. Men of ages 18-60 are prohibited from leaving Ukraine and must stay and defend the country. In early March, one 11-year-old boy was welcomed into Slovakia after crossing the border alone. He fled the country and traveled 1,000 kilometers (about 620 miles) by himself without his mother, who was caring for her own mother who wasn’t healthy enough to leave.

People leaving Ukraine have fled to Poland, Romania, Moldova, Slovakia, Russia, and Belarus. Poland has received by far the most refugees, with over 2 million people coming into the country. They have largely been met with support from local governments and residents, and the refugees have the opportunity to apply for an ID number that qualifies them to get healthcare and access to emergency services.

Many refugees do not stay in the initial countries that they flee to, and many Western countries have announced programs to help facilitate the continuing flood of Ukrainians who are seeking a place to live before they can return to their homes.

If you would like to help contribute to humanitarian aid for Ukrainians impacted by this war, CNN has compiled a list of 40 organizations working to aid those in need.