Article: Greece was eventually occupied by the Nazis who proceeded to administer Athens and Thessaloniki, while other regions of the country were given to Nazi Germany's partners, Fascist Italy and Bulgaria. The occupation brought about terrible hardships for the Greek civilian population. Over 100,000 civilians died of starvation during the winter of 1941–1942, tens of thousands more died because of reprisals by Nazis and collaborators, the country's economy was ruined and the great majority of Greek Jews were deported and murdered in Nazi concentration camps. The Greek Resistance, one of the most effective resistance movements in Europe fought vehemently against the Nazis and their collaborators. The German occupiers committed numerous atrocities, mass executions, and wholesale slaughter of civilians and destruction of towns and villages in reprisals. In the course of the concerted anti-guerrilla campaign, hundreds of villages were systematically torched and almost 1,000,000 Greeks left homeless. In total, the Germans executed some 21,000 Greeks, the Bulgarians 40,000 and the Italians 9,000.

Question: What civilian group in Greece fought against Nazi occupation?
The Greek Resistance