Finland officially joined NATO in a ceremony on Tuesday, April 4, becoming the alliance’s 31st member.Finnish Foreign Affairs Minister Pekka Haavisto joined NATO Secretary-General Jens Stoltenberg and US Secretary of State Antony Blinken to formally hand over the accession documents at NATO headquarters in Brussels.In a statement, Finland’s president, Sauli Niinisto, said NATO membership “strengthens our international position and room for maneuver” and “provides security for Finland.”Finland submitted its application to join NATO alongside Sweden in May of 2022, months after neighbor Russia invaded Ukraine, ending decades of non-alliance.Stoltenberg said the Finnish flag would soon be raised outside NATO headquarters. Credit: Oana Lungescu via Storyful