Before and after World War II, thousands of men in Estonia went into the forest to escape the repressions of foreign powers. There were many reasons for this – they were either afraid of being mobilized into the Soviet or German armies, wealthy farmers were afraid of being deported to Siberia; men who had voluntarily or forcibly served in the German army fled to escape arrest. A lot of them sustained the hope that the Republic of Estonia would soon be restored with the help of foreign countries.
Underground bunkers suitable for year-round living were built in higher forests, and the men who were forced to live this life were called Forest Brethren. The Soviet authorities carried out a ruthless hunt for them, and thus the great majority of the men who hid in the forest were killed or sent to Siberia after being captured. The last Nordic Robinsons voluntarily left the forest as late as in the early 1970s.
Estonian Forest Brethren website: