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. Stoltenberg said the Finnish flag would soon be raised outside NATO headquarters. Credit: Oana Lungescu via Storyful