Following Russia's military invasion of Ukraine, Sweden, which was considering applying for NATO = North Atlantic Treaty Organization, officially decided on the 16th to apply for membership in NATO.
Sweden is a major policy shift as it has been military-neutral for almost 200 years.
Finland, a neighboring country, has just announced on the 15th that it will apply for NATO membership.
Both countries want to apply for membership together, and it is expected that they will formally apply in the near future.