Underground, in political terms, is a secretly conducted movement to overthrow the government or the military occupation forces of a country. Underground tactics have been used since early history, but reached a high point of activity during World War II (1939-1945). Since then, Communist organizations have worked underground in attempts to overthrow many governments.
During World War II, especially in the early stages, Germany’s Adolf Hitler used an underground group called the fifth column (see Fifth column ). German agents worked inside various countries before and during the German invasions of those countries. The agents used espionage, propaganda, and sabotage to aid the German cause and hurt an invaded country’s morale.
But once the Germans had conquered a country, the underground of that country’s patriots hampered German operations. Underground workers sprang up in France, Belgium, the Netherlands, Denmark, Norway, Yugoslavia, occupied areas of the Soviet Union, and other conquered areas. They plagued the Germans by blowing up railroad trains and bridges, sabotaging factories, distributing illegal newspapers, rescuing marooned Allied servicemen, and gathering valuable military information.
