Finland joined the NATO military alliance Tuesday, dealing a major blow to Russia with a historic realignment of the continent triggered by Moscow’s invasion of Ukraine. With the handing over of documents, the Nordic nation officially entered the world’s biggest security alliance, doubling its border with Russia. 

Finland’s membership represents a major change in Europe’s security landscape: The country adopted neutrality after its defeat by Soviets in World War II. But its leaders signaled they wanted to join the alliance just months after Russian President Vladimir Putin’s invasion of Ukraine sent a shiver of fear through Moscow’s neighbours.