How to defend yourself from an invasion. This is how Finland has been preparing for 80 years

The invasion of Ukraine has prompted many to ask themselves: what if it happened to us too? There are obviously differences, geographical and geopolitical: a NATO member country has a protection that Ukraine does not have. But Russian aggression sows uncertainty and there is a country in Europe that offers a model. This is how Finland has been defending itself against such a threat for eighty years.