Sweden is the latest country to join NATO, last month. Around the Baltic Sea, nations are all worried about what Vladimir Putin might do, after showing he is capable of invading his Ukrainian neighbor. Sweden officially ended its traditional neutrality and its Prime Minister even told his fellow citizens that they must prepare for war... Military service was also reinstated in 2018. Our reporters Julien Sauvaget and Clovis Casali visited the island of Gotland, considered by experts to be the most strategic place in the Baltic Sea.