After Italians had attacked Greece and were successfully repulsed by the Greek army, the war became part of the everyday life of the Athenians. In January 1941 the Italians bombarded Piraeus and other towns of Greece, with many victims among the civilians. On the 29th of January 1941 Metaxas died and was replaced by Alexandros Koryzis who allowed the British troops to enter Greece; this was the official pretext of the Germans to declare the war to Greece. On the 6 th of April the Nazis, with a blitzkrieg achieved to occupy the entire Balkans, except Crete, in less than a month. On the very first day of German attack, Piraeus was bombarded again, causing tragic human loss and damages, as one of the bombs fell on a British vessel that carried nitroglycerin; the explosion resulted in extensive damages not only at Piraeus but also in entire Athens.

Very soon, the actions of resistance started in Athens. The first, highly symbolic event was the lowering of the German flag from the Acropolis; early in the morning of the 31st May 1941, two brave young men, Manolis Glezos and Apostolos Santas achieved to escape the German guards and lower the swastika from the Acropolis. Soon after, the resistance was organized in a better way; fly-bills and hand-bills issued by small resistance committees and associations appeared everywhere in Athens. On the 27th of September 1941, communists, democrats and other patriots established EAM (National Liberation Front) which proved to be the most important organization in the period of German occupation.

The winter 1941-1942 was really tough in entire Greece, especially in the towns; Athens was not an exception. The population had to face a severe winter along with a lack of food and provisions. As a result some 300.000 people died of starvation in Athens, Piraeus and the suburbs. As time passed things became better, thanks to the action of the resistance organizations that saved the population of the city from starvation and death. Also, the British had allowed the Red Cross to supply Greece, mainly Athens, with food and medicines.

Resistance was manifested in various ways: in arms or without, in sabotages, in graffiti on the walls of the city, in mass manifestations, in participating to resistance organizations. Several events are worth citing: the manifestations on the anniversary of the war, on the 28th of October, the reaction of the population of Athens which prevented Germans from sending manpower in the industries of Germany, the acts of hiding Jews, so that they would not be seized by the Germans, the dynamiting of the seat of ESPO, an organization of collaborators of the Germans; this latter had hundreds of victims, both Germans and Greek traitors. During the last year of occupation, the acts of resistance became much more organized and efficient: now, real battles took place between the conquerors and their collaborators and the army of the resistance.

Germans responded to the reactions with persecutions, incarcerations, executions and slaughters of civilians in several quarters of Athens where resistance was strong, as Kokkinia (Nikaea), Kesariani and Nea Smyrni. Hundreds of Greek patriots were seized and brought to the camp at Haidari, were the majority was condemned to death and executed. The best known episode of mass execution in Athens was the one that took place in Kesariani on the 1st of May 1944, when 200 patriots were executed by the Germans.

In August 1944 the German military leaders had decided to remove their troops from Greece as they risked to be trapped by the Soviet Army that advanced rapidly towards the Balkans. In this period German atrocity reached its peak: mass arrests and executions took place in the quarters of Athens, as well as strong and bloody battles between the German troops and ELAS, the partisan army, which had already set free several areas of Athens as Kesariani and the rest of the eastern quarters.